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Wikijunior:Dinosaurs/Pterosaurs

Pterosaurs are commonly referred to as Pterodactyls. However scientists prefer Pterosaurs, so this name is used in this book. Pterosaurs are not dinosaurs ("fearfully great lizards"), they are a close relative and lived alongside dinosaurs and died out during the same period. Due to their more avian nature (bird like) they are even often simply referred as birds in the context of that era, but our understanding is that their branch (in the tree of evolution of species) does not link to modern birds.

On the Ground
As well as flying probably very large distances due to the different atmospheric content (dense oxygen-rich atmosphere). Pterosaurs could move on the ground and needed to as to be able to take flight. For a while scientists didn't know if this was using two feet (bipedal), or using four feet (quadrupedal). We now know that they used four, from fossil footprints. However, we don't know if they did this all the time. Some scientists think that small Pterosaurs could walk or even run on two feet, but larger ones used all four like bats do now.

Body shape
The different types of pterosaurs all had different sizes. Ranging from 0.75m wingspan and of the Pterodactylus to 11 meters wingspan and 135 kg weight of the Quetzalcoatlus. Quetzalcoatlus was the largest pterosaur, its wingspan being 45 feet.

The pterosaurs are divided into two groups; the Rhamphorhynchoids had no crests and tails, while the Pterodactyloids had crests but no tails.

Most large Pterodactyloids had crests on their head, possibly colored brightly, but different types of Pterodactyloids had differently shaped crests. All were narrow, but some stretched out behind their head in a triangle shape (as in the picture on the left), while others were small rounded humps on top of their heads.

They didn't have feathered wings, like today's birds do, but some scientists think they might have had fur, like bats! They might have been for warmth, just like bats!

What did they eat?
Pterodactyls were carnivores and scavengers. In the first few months of their life, they ate insects. As an adult they ate a lot of fish which they would catch from the surface of the water by dipping their long beaks in as they flew over, but they would also eat dinosaurs who were already dead.

When did they live?
The Pterosaurs lived all through the mesozoic era. The Rhamphorhynchoids lived in the Triassic and early Jurassic periods; and the Pterodactyloids in late Jurassic and Cretaceous periods.

Where did they live?
It is believed that most of the species of Pterosaurs lived close to the sea shores, as to have easy access to fish and ample space to fly and glide with the benefit from different temperatures in air columns (hot to climb and cold to drop). Like some modern birds they seem to form large groups and behaviour should have been as varied as with today's bird species. Some Pterosaurs fossils have even been found in caves.

They lived in some parts of America, Guam, China, Japan, England, Germany, France, Tanzania (in Africa) and many other places too.

When and how they were discovered?
Different types of pterosaurs were discovered at different times. The earliest to be found was the Pterodactylus in 1784 in France by the Italian scientist Cosimo Collini. He didn't think they could fly but thought they could swim. This seems silly now that we know they have wings. Another species was discovered in 1876 by Othneil C. Marsh, and one of the most recently discovered the gigantic Quetzalcoatlus found by Douglas A. Lawson. New discoveries are still being made; in the 1990s there were several discoveries made to suggest that even a larger pterosaur could have existed than previously known (Arambourgiania philadelphiae).

How were they wiped out?
The last of the larger Pterodactylids seems to have been killed in the K-T extinction, along with the dinosaurs. However, the Rhamphorynchids seem to have been extinguished earlier, probably because they could not compete with birds (which evolved around that time).

What do we need to learn?

 * What colour were they?
 * What were the crests on their heads used for?
 * Were they really scavengers?
 * Were they all covered in fur?

Links
Dinosaur Time Machine: Pterodactyls

title: Wikijunior:Dinosaurs/Pterosaurs


text:
Wikijunior:Dinosaurs/Triceratops

What did they look like?
The body of the Triceratops was big and round, planted on top of short sturdy legs. It was 8 meters long, about 3 meters tall and weighed somewhere between 6 and 12 tons (the size of an elephant).

Triceratops means "Three Horned Face" in Greek. It is called that because it had three horns – two above its eyes and one on its nose. Triceratops horns could be up to 115 cm (45 inches) long. It had a big frill that extended up above the head.

The horns were used for defense, against such enemies as the Tyrannosaurus. When threatened, the Triceratops would stand and fight. Its sharp horns would act as spears and cause a lot of damage. It also had a powerful bite.

Scientists do not all agree on what its head frill was used for. Some say it could have been a defense – like a shield, to protect its body. Some say it was used to give a warning to members of the herd by changing colour. Many now believe the horns and frill were used for social behavior and communication between different Triceratops individuals. For example, two bull Triceratops used the horns and frill in fights over territory or mates, the same way bovids and antelopes do today.

What did they eat?
The Triceratops was a herbivore — a plant-eater — that fed close to the ground. We know this because it had flat teeth that are good for chopping up vegetation, and its massive head would have been difficult to lift high in the air. Unlike any animal today, the Triceratops had a beak in front of its mouth and teeth in the back. The beak would have a hard covering like a parrot beak.

A triceratops' teeth would have been able to crush not only leaves but even very tough branches and roots. Some scientists think Triceratops ate cycads, which are a type of plant that was common in the Cretaceous. These plants look like a small palm tree with a crown of sharp, spiky leaves. A Triceratops could have used its strong beak to strip off the leaves before eating the trunk. Other scientists argue that these plants are very poisonous so it is unlikely that any dinosaur ate them, even though today the sloth and other animals like the parrot (a descendant of the dinosaurs) can eat poisonous leaves or fruit.

Triceratops, like any animal that eats tough foods, had to be big: they needed to process the food very slowly because it took a long time to digest, requiring a long digestive tract. This is evident in how, for instance, an elephant can digest a tree branch, or a cow can digest hay, but a human cannot.

When did they live?
Triceratops lived in the late Cretaceous period, around 66 to 68 million years ago. The climate was warm and dry and there were numerous volcanoes.

Where did they live?
Triceratops lived in the North American continent. Remains have been found in the United States (USA) states of Colorado, Montana, North and South Dakota, and Wyoming, and in the Canadian provinces of Alberta and Saskatchewan. There is evidence that they were a herding animal. They lived in groups like buffalo or bison.

How were they discovered?
The first Triceratops was discovered in 1887, in Colorado, USA. Since then many of their fossils have been found with Tyrannosaurus tooth marks!

What do we need to learn?
Wikijunior Dinosauri/Triceratops
 * What their head frill was used for. - Some people believed that the Triceratops babies were hunted by smaller meat eaters and the adult used their frills to protect their young.
 * If they were really hunted by T.Rex.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Wikijunior:Dinosaurs/Triceratops


text:
Wikijunior:Dinosaurs/Plesiosaur

The Plesiosaur is not actually a dinosaur, but rather a large swimming reptile. Plesiosaur is Greek for "nearer to the reptiles". This name given to this creature because it resembles something that is part reptile and part fish. The whole group of these animals are called plesiosaurs.

What did they look like?
There were different types of Plesiosaurs which were different from each other in size and in shape. The shortest were 2.5 metres long and the longest were 14 metres long! That is about as long as 8 adults lying in one long line! Some had long necks with small heads on the end, others had short necks with immense jaws (pliosaurs). Their stomachs were oval-shaped with two front flippers and two back flippers. They had long tails, though much shorter than their necks.

Scientists first thought that they swam close to the surface of the water (as the picture on the left shows). This way they could stick their head above the water and look down on fish. But because their eyes are placed facing slightly upwards, this is probably not true. They probably swam completely underwater and used their long necks to dart their heads towards fish. Plesiosaurs and their relatives were very successful.

What did they eat?
Their tooth structure and gut remains showed they ate mostly invertebrates, so things like cephalapods. They ate fish, squids, mollusks and other small sea creatures. Recently, scientists have found evidence that the Plesiosaurs may have also been "bottom-feeders". That is, they would feed from the bottom of the sea - on things like clams and snails.

When did they live?
They lived from the early Jurassic to the end of the Cretaceous period. That is from about 220 million years to about 66 million years ago. Plesiosaurs, like dinosaurs, lived in the Mesozoic era. Nobody is sure why the plesiosaurs went extinct.

Where did they live?
Some people think that they could climb out of the water and crawl around on land, like seals. But other scientists disagree with this. Either way they would have spent a lot of their time under water. And because they were air-breathing animals, they would have to come up to the water surface for air every now and then.

Their fossils were found in England, Germany, Korea, Australia, New Zealand and USA. They also lived in Manitoba, Canada,and Mexico

How were they discovered?
The first Plesiosaur was discovered in 1821 by Mary Anning, in England. Mostly found in the Benthic zone, they can also be found in the intertidal zones as well.

Modern mysteries around the Plesiosaurs
The most famous mysteries around these creatures is the Loch Ness Monster. There are a lot of stories of some large creature in the lake called Loch Ness in Scotland. Most descriptions of the monster are close to what the Plesiosaurs must have looked like. Some of the sightings have been proven to be a hoax and at present there is no scientific proof of the existence of the animal but many people believe in it. The study and search for animals which fall outside of contemporary zoological catalogues has the name of Cryptozoology.

In 1977, some Japanese fishermen off the coast of New Zealand found a very rotten carcass of some large creature with flippers. It was so rotten that it was very hard to tell anything from it, but some people believed that it was a plesiosaur. Scientists however ascertained it was a basking shark, fallen to bits because it was so rotten.

What do we need to learn?

 * How flexible were their necks? Scientists don't agree on this.
 * Is there any truth to the stories around them?

Wikijunior Dinosauri/Plesiosaur

title: Wikijunior:Dinosaurs/Plesiosaur


text:
Wikijunior:Dinosaurs/Velociraptor

Velociraptor means "swift thief". This is a good name because Velociraptor was a small dinosaur that could run fast (up to about 64 km/h (40 mph)). It also could jump about 10 feet straight up. Velociraptor was a theropod. The theropods were a group of dinosaurs that walked on two legs. This group of dinosaurs are the ancestors of birds. Velociraptor brains were bigger than most other dinosaurs compared to the size of their bodies. Velociraptor was a smart dinosaur for its time.

What did they look like?
The Velociraptor was just under a meter tall (about three feet), usually about 5-6 feet long from nose to tail, and weighed anywhere from 7-15 kilograms (15-33 pounds). Velociraptor had feathers on its skin, the same as birds do today. These dinosaurs walked on two legs and had two hands with three fingers and sharp claws. Their heads were long and narrow like a crocodile, and had a mouth with 26 or more teeth which was able to close very quickly. On each foot, they had a large dangerous curved toe claw. Their claws could grow up to 5 inches long. Velociraptor had a stiff tail that it used for balance. The tail could only flex from side to side, not up and down; this helped the dinosaur run fast and change directions quickly. Velociraptor had two legs which means it was bipedal. Its legs were strong and sturdy and it may have used them to jump. Velociraptors were also very agile.

What did they eat?
Velociraptor was a carnivore. This means that it ate meat. It slashed or punctured its victims with its very long toe claw. Whether closely related dinosaurs like Deinonychus hunted in packs is not known because no evidence has been found.

Alone a Velociraptor could have killed and eaten animals like lizards, early mammals and small or young dinosaurs. In a pack, Velociraptor may have hunted even larger prey such as Homocephale, a pachycephalosaur. One meal that was definitely on a Velociraptor’s menu was Protoceratops. Protoceratops was a plant-eating dinosaur that was a relative of Triceratops, but had no horns and was the size of a pig. Scientists have found a fossil of Velociraptor locked in a fight with a Protoceratops. The animals killed each other during the fight and a sand dune collapsed on top of them.

In a group, Velociraptor could have quickly and quietly circled around an animal that was alone to trap it. Velociraptor hunted by separating a victim from the herd. They killed their prey like today's eagles. Velociraptor would sneak up on its prey and pounce on it, then it will pin its prey to the ground with its claws and body weight and then eat it. This technique is called Raptor Prey Restraint (RPR).

When did they live?
Velociraptors lived during the Late Cretaceous period, about 80 - 85 million years ago. This was only 15 million years before the dinosaurs became extinct. The world was much hotter than it is today, and there were no polar ice caps. There were small mammals and birds living at the same time as Velociraptor. There were flowering plants and many insects similar to the ones we see today.

Where did they live?
Velociraptor lived in Asia. Fossils have been found in Russia, China and Mongolia. They lived in a place that was hot and covered by sand dunes. There were streams of water close to where some fossils have been found. They may have lived near the water and preyed on animals that came to drink. Some predators do this today.

The related dinosaur Deinonychus lived in what is now the United States.

How were they discovered?
The first Velociraptor was discovered by the paleontologist Peter Kaisen in the Mongolia desert in 1923. A paleontologist is a scientist that studies dinosaurs. The first fossils found were a skull with jaws and some toes with a claw. The skull was found next to a Protoceratops skull. Paleontologists have found 12 different examples of the animal so far.

Velociraptors and Jurassic Park
In popular films called Jurassic Park, the Velociraptor ultimately did not look like it would have in real life. The film's Velociraptors were twice as tall as they really were, they were scaly instead of feathered, and their tails were too flexible. A real Velociraptor was only about 1.6 ft (about 0.5 m) tall. The "raptors" in Jurassic Park however looked like Deinonychus, that was also Velociraptor's bigger cousin. But do not let that fool you, these little creatures were also swift, powerful, and would still have no problem killing you.

What do we still need to learn?

 * How did they use their long claw when hunting? Did they slash or stab with it? It is not likely they slashed at their prey, as their claws were more designed for gripping, and were too brittle to rip through flesh. So, they most likely used it to stab in and then wiggle it to tear through and rip prey.
 * Did they really hunt in packs? All the fossils found have been alone.
 * Did they live in packs or did they live alone?
 * How much did they eat each day?
 * Why did they go extinct?
 * What did they use their feathers for?
 * If they did not hunt in packs, why did they attack such large prey?

Wikijunior Dinosaurukset/Velociraptor Wikijunior Dinosauri/Velociraptor fa:ویکی‌کودک:دایناسورها/دزد چابک

title: Wikijunior:Dinosaurs/Velociraptor


text:
User talk:212.219.57.50

Please stop adding nonsense to Wikibooks. It is considered vandalism. If you would like to experiment, use the sandbox. Thank you.

title: User talk:212.219.57.50


text:
User talk:200.121.252.20

Please stop adding nonsense to Wikibooks. It is considered vandalism. If you would like to experiment, use the sandbox. Thank you.

title: User talk:200.121.252.20


text:
User talk:59.176.20.243

Please stop adding nonsense to Wikibooks. It is considered vandalism. If you would like to experiment, use the sandbox. Thank you.

title: User talk:59.176.20.243


text:
User talk:163.191.101.2

Please stop adding nonsense to Wikibooks. It is considered vandalism. If you would like to experiment, use the sandbox. Thank you.

title: User talk:163.191.101.2


text:
Topology/Sequences

A sequence in a space $$X$$ is defined as a function from the set of natural numbers into that space, that is $$f:\mathbb{N}\to X$$. The members of the domain of the sequence are $$f(1),f(2),\ldots$$ and are denoted by $$f(n)=a_n$$. The sequence itself, or more specifically its domain are often denoted by $$\left\langle a_i\right\rangle$$.

The idea is that you have an infinite list of elements from the space; the first element of the sequence is $$f(1)$$, the next is $$f(2)$$, etc. For example, consider the sequence in $$\mathbb{R}$$ given by $$f(n) = 1/n$$. This is simply the points $$1,1/2,1/3,1/4,...$$ Also, consider the constant sequence $$f(n) = 1$$. You can think of this as the number 1, repeated over and over.

Convergence
Let $$X$$ be a set and let $$\mathcal{T}$$ be a topology on $$X$$

Let $$\left\langle x_i\right\rangle$$ be a sequence in $$X$$ and let $$x\in X$$

We say that "$$\left\langle x_i\right\rangle$$ converges to $$x$$" if for any neighborhood $$U$$ of $$x$$, there exists $$N\in\mathbb{N}$$ such that $$n\in\mathbb{N}$$ and $$n>N$$ together imply $$x_n\in U$$

This is written as $$\lim_{n\to\infty}x_n=x$$

Exercises
(i) $$1,2,3,4,5\dots$$ (ii) $$2,-4,6,-8,10,\ldots$$
 * 1) Give a rigorous description of the following sequences of natural numbers:

Let $$U_1\subset U$$ and $$x\in U_1$$. Similarly construct neighbourhoods $$U_i\subset U_{i-1}$$ with $$x\in U_i\forall i$$. Let $$\left\langle x_i\right\rangle$$ be a sequence such that each $$x_i\in U_i$$.
 * 1) Let $$X$$ be a set and let $$\mathcal{T}$$ be a topology over $$X$$. Let $$x\in X$$ and let $$U$$ be a neighbourhood of $$x$$.

Prove that $$\lim_{n\to\infty}x_n=x$$

title: Topology/Sequences


text:
User talk:Mastermind 007

Welcome
Hello and welcome to Wikibooks.

Thanks for contributing to Civilistation wikibook but there are some things that need to be fixed. Firstly, you created duplicated modules: Civilization IV and Civ:Civilization IV. Decide which one you want to develop and mark other with delete template so that we know it can be safely deleted. Secondly, you should use proper naming convention in your book. You shouldn't name pages like Chapter 1 - Leaders. It should be: Civilisation IV:Leaders or Civilisation IV:Leaders.

If you have any questions, use my talk page. --Derbeth talk 19:50, 5 January 2006 (UTC)

Copyright Violations
As much as I am thankful that you contributed to the Civilization wikibook, I am saddened by the fact that you copy/pasted it from gamespot. Please, don't do another copyright violation. --Dragontamer 01:59, 16 January 2006 (UTC)

 * I'm going to add to this here. If you are contributing to Wikibooks and adding the content, it is up to you, the author, to provide verification that you have copyright clearance.  If you want to do the legwork and ask Sid Meier for explict permission to release this gaming guide on Wikibooks under the GFDL, go ahead.  Please provide either a link to or a copy of that permission, with a link to an e-mail address or something that could be used to provide verification that the permission was granted.  Otherwise it will have to be deleted as this is an explicit violation of copyright.  Gamespot is copyighted with the terms "all rights reserved" and is subject to criminal penalties in many nations that could get you into jail for doing things like this.  For legal reason we simply can't have stuff like this on Wikibooks.  --Rob Horning 15:06, 17 January 2006 (UTC)

How To Be A Good Student
Hi, I was perusing your wikibook "How to Be A Good Student" and I would like to suggest that you heavily edit some of the pages in your book. There are many problems with your use of English, and as an English-native speaker, I find the entire book extremely confusing and often vague and deficient in its purpose. If you would like me to assist you in your writings, please contact me, and I will do so. Otherwise, I'll start editing your book to better convey your sentiments. —the preceding unsigned comment is by Pengson (talk • contribs) 07:07, 18 January 2006 (UTC)

Hello, Murtaza :) I was hoping you would give my post ("Failed Editing Attempts") on the discussion page of your book, "How To Be A Good Student" a read. Thanks in advance. Wikibooks Discussion Post --24.175.54.43 06:38, 7 July 2006 (UTC)

Unidentified Contact
Hello Thank You for sending me a suggestion but I cannot identify who you are (the one who wrote the "How To Be A Good Student). Please write your username so I can identify you. —the preceding unsigned comment is by Mastermind 007 (talk • contribs) 17:02, 18 January 2006 (UTC)

The Elements
You are listed as either an interested participant or voted for "The Elements" for Wikijunior New Book of the Quarter. This message is to let you know that we are starting work on The Elements because it was selected for 4th quarter 2006. --xixtas 03:31, 4 October 2006 (UTC)

title: User talk:Mastermind 007


text: User talk:12.151.148.98

title: User talk:12.151.148.98


text: User talk:70.231.246.43

title: User talk:70.231.246.43


text:
Talk:LPI Linux Certification/LPIC2 Exam 202

Naming policy
I am moving subpages (and updating the main page accordingly) to conform with Naming policy. --JMRyan 20:04, 5 January 2006 (UTC)


text:
User talk:JakeH

My Own Page!

Lol, I have my own page!

See!

My page!

title: User talk:JakeH


text:
User talk:AlexeySmirnov

Hello, welcome to Wikibooks! I noticed that you made the GNU C Compiler Internals module. However, it looks like that you copied it from the Internet without permission. A sysop will delete it unless there was copyright permission to use the text at Wikibooks.

So that Wikibooks is free, we have a copyrights policy that uses the GNU Free Documentation License. --Kernigh 21:38, 5 January 2006 (UTC)

I am the copyright holder of the text at the URL http://www.ecsl.cs.sunysb.edu/gem/gem.html AlexeySmirnov 22:09, 5 January 2006 (UTC)

title: User talk:AlexeySmirnov


text:
Talk:GNU C Compiler Internals

The author of this text is the copyright holder of the text at this web page:

http://www.ecsl.cs.sunysb.edu/gem/gem.html

AlexeySmirnov 22:03, 5 January 2006 (UTC)

 * Sorry. If you are the copyright holder, then I will not mark it copyvio again. Thanks for making the text available to Wikibooks!

 * Wikibooks had this situation at least twice before: a user uploads something they own and already published, then other users call it a "possible copyright violation". --Kernigh 02:06, 6 January 2006 (UTC)

GCC internals manual
There's already an "official" GCC internals manual from the FSF, licensed under the GFDL. If we really want to also have a wikibook, why not start with the FSF manual's contents? 71.141.251.153 04:57, 7 January 2006 (UTC)

GEM ?
Are "GCC Extensibility Modules" part of GCC suite ? Since most part of the book is about GEMs I think the title is misleading. Please change it to something like "Using GEMs with GCC", indeed this book says really little about GCC internals.

Thanks, --82.51.137.43 18:54, 15 September 2006 (UTC)

Note to editor
There is a spelling error in this page, but editing it gives access to only the last three lines. The spello is "througout".
 * ✅. It now says "throughout". --DavidCary (talk) 04:18, 19 January 2009 (UTC)

title: Talk:GNU C Compiler Internals


text:
C Sharp Programming/Inheritance

Explanation By Analogy
What is the benefit of inheritance?

 * 1) It saves you a lot of typing
 * 2) It saves you from repeating yourself.

Inheritance explained by analogy

Suppose you want to create an Eagle, a Falcon and a vulture. In order to create these flying creatures you notice that each of these creatures:
 * 1) Fly
 * 2) Breed
 * 3) Eat

Let us assume for the sake of argument that all three types of birds: fly, breed and eat in exactly the same way.

Without inheritance, you would be forced to copy code. i.e. the same code which causes an eagle to fly would also be copied to make the vulture fly. And it is axiomatic to programmers - who are a lazy bunch, not wanting to repeat themselves - that repetition is almost always a bad thing.

Note the eagle, falcon and vultures are all in fact birds. Accordingly, you could say that a bird, generally speaking, always has the characteristics of eating, breeding and flying. So using "inheritance" you could create generic 'bird' prototype, which eats, breeds and flies, and then once that is defined, you can have all other specific breeds of birds inherit those characteristics. In other words, using the prototype, you can design other specific birds off that prototyped design.

This means that the falcon automatically knows how to fly because it inherits that behaviour from the general Bird class. You basically don't have to repeat yourself.

Inheritance
Inheritance is the ability to create a class from another class, the "parent" class, extending the functionality and state of the parent in the derived, or "child" class. It allows derived classes to overload methods from their parent class.

Inheritance is one of the pillars of object-orientation. It is the mechanism of designing one class from another and is one of the ideas for code reusability, supporting the concept of hierarchical classification. C# programs consist of classes, where new classes can either be created from scratch or by using some or all properties of an existing class.

Another feature related to inheritance and reusability of code is polymorphism, which permits the same method name to be used for different operations on different data types. Thus, C# supports code reusability by both features.

Important characteristics of inheritance include:

 * 1) A derived class extends its base class. That is, it contains the methods and data of its parent class, and it can also contain its own data members and methods.
 * 2) The derived class cannot change the definition of an inherited member.
 * 3) Constructors and destructors are not inherited. All other members of the base class are inherited.
 * 4) The accessibility of a member in the derived class depends upon its declared accessibility in the base class.
 * 5) A derived class can override an inherited member.

An example of inheritance:

Subtyping Inheritance
The code sample below shows two classes, and. has the methods and.

We want the class to have the same methods, but differently implemented and one extra method,.

Below is the creation of the first class to be derived from.

Now, we create an class that will override the  method:

You'll notice that there is no method in the  class, as it is inherited from.

Virtual Methods
If a base class contains a virtual method that it calls elsewhere and a derived class overrides that virtual method, the base class will actually call the derived class' method:

Constructors
A derived class does not automatically inherit the base class' constructors, and it cannot be instantiated unless it provides its own. A derived class must call one of its base class' constructors by using the keyword:

Inheritance keywords
The way C# inherits from another class syntactically is by using the operator.

Example:

To indicate a method that can be overridden, you mark the method with.

To override a method, use the  keyword:

A missing or  keyword for a derived method may result in errors or warnings during compilation.: Here an example:

The class method  will result in a compilation error, if it is derived from the  class:

error CS0534: 'ConsoleApplication3.Square' does not implement inherited abstract member 'ConsoleApplication3.Shapes.Area'

The same method will result in a compilation warning, if derived from the normal class:

warning CS0114: 'ConsoleApplication3.Square.Area' hides inherited member 'ConsoleApplication3.Shapes.Area'. To make the current member override that implementation, add the override keyword. Otherwise add the new keyword.

title: C Sharp Programming/Inheritance


text:
C Sharp Programming/NET assembly

=Assemblies and Manifests=

A Microsoft dotNET Assembly is an exe or dll. Assemblies are the basic unit of deployment. An assembly consists of 4 components:
 * 1) Assembly Metadata (also known as Assembly Manifest)
 * 2) *This is sort of like a packaging list of everything that is required for this assembly to work. A manifest contains:
 * 3) *#Version requirements
 * 4) *#Security Identity
 * 5) *#Scope of assembly
 * 6) Type Metadata
 * 7) IL (Intermediate Language)
 * 8) Resources

title: C Sharp Programming/NET assembly


text:
C Sharp Programming/NET Framework overview

.NET Framework is a common environment for building, deploying, and running Web Services, Web Applications, Windows Services and Windows Applications. The .NET Framework contains common class libraries - like ADO.NET, ASP.NET and Windows Forms - to provide advanced standard services that can be integrated into a variety of computer systems.

Introduction
In June 2000 Microsoft released both the .NET platform and a new program language called C#. C# is a general-purpose OOP language designed to give optimum simplicity, expansiveness, and performance. Its syntax is very similar to Java, with the major difference being that all variable types are derived from a common ancestor class.

C# is a language in itself. It can perform mathematical and logical operations, variable assignment and other expected traits of a programming language. This in itself is not flexible enough for more complex applications. At some stage, the developer will want to interact with the host system whether it be reading files or downloading content from the Internet.

The .NET framework is a toolset developed for the Windows platform to allow the developer to interact with the host system or any external entity whether it be another process, or another computer. The .NET platform is a Windows platform-specific implementation. Other operating systems have their own implementations due to the differences in the operating systems I/O management, security models and interfaces.

Background

 * Originally called NGWS (Next Generation Windows Services).
 * .NET does not run in any browser. It is a runtime language (Common Language Runtime) like the Java runtime. By contrast, Microsoft Silverlight does run in a browser.
 * .NET is based on the newest Web standards.
 * .NET is built on the following Internet standards:
 * HTTP, the communication protocol between Internet Applications
 * SOAP, the standard format for requesting Web Services
 * UDDI, the standard to search and discover Web Services
 * XML, the format for exchanging data between Internet Applications


text:
User talk:TantalumTelluride~enwikibooks

If you want to contact me as quickly as possible, please use my Wikipedia user talk page.

Cows... again
I haven't noticed it. Thanks, I deleted it again. --Derbeth talk 07:29, 18 January 2006 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called TantalumTelluride. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name TantalumTelluride~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:45, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 05:35, 19 April 2015 (UTC)

title: User talk:TantalumTelluride~enwikibooks


text:
Talk:LPI Linux Certification/LPIC2 Exam 201

Naming policy
I have moved subpages (and updated links accordingly) to conform with Naming policy. --JMRyan 20:04, 5 January 2006 (UTC)


text:
User talk:204.111.141.74

Please do not restore deleted content. --Derbeth talk 23:56, 5 January 2006 (UTC)

title: User talk:204.111.141.74


text:
Talk:TI-Basic Z80 Programming/List of Commands/If

Correction
I took out this section because it didn't work on my TI-83

When using If to regulate the execution of more than one instruction, it is important to indicate the end of the set of instructions with an End. Without the End, only the instruction immediately follwing the If statement will be reguated while the rest will be executed indifferent to the value of the criteria.

For example:

[...]
 * If X>3
 * Disp "Hello World!"
 * Disp "My Name is Seth"

[...]

will display "Hello World!" followed by "My name is Seth" if X (the user's input) is greater than 3, and will display only "My name is Seth" if X is less than 3. This is beacsue :Disp "My Name is Seth" is executed regardless what the value of X is. Meanwhile,

[...]
 * If X>3
 * Disp "Hello World!"
 * Disp "My Name is Seth"
 * End

[...]

will display "Hello World!" followed by "My name is Seth" if X is greater than 3 and will display nothing if X is less than 3. This is because the execution of all the intructions between If and End is regulated by the criteria stated after If.


text:
Talk:Chess/Strategy

Zigzwang
i edited the zigzwang module,jus a bit,felt the definition was not clear or even wrong,i think even the explanation have to be rewritten. fanx-johnson

I agree, I think that it should be clearer. I don't think I'm the person to do it as I'm someone who understands the game but is not knowledgable in the game. Perhaps make it clearer that the pawn is protected (rook or bishop) and define why the king cannot simply move in front of the pawn. --Nathan 22:42, 6 January 2006 (UTC)--207.54.103.2 22:41, 6 January 2006 (UTC)

Capitalization
Just wanted to ask...do we capatalize piece names "Bishop, Knight" regardless of their position within a sentence or not? I have seen this applied randomly and just wanted to check.

--IRelayer 20:46, 12 January 2006 (UTC)

King worth 3.5?
This doesn't make sense to me. Is there citation to explain how the King could be worth 3.5 (and thus logically worth less than both a rook and a queen) when the entire point of the game is to capture the other player's King while defending your own? The King's value should be infinite.
 * The non-royal equivalent piece known as Man or Mann (Commoner) is within a knights value. So an royal king with all his check restrictions should not gain +0.50 additional value just because it's royal and always remains on the board. The mate vulnerability is a big negative to the total piece value. While i do agree that the King is often reckoned as the strongest piece in minor piece endgames. A value of 3.25 or close to 3.35 make more sense in my book (endgame). --Sunny3113 (discuss • contribs) 18:00, 9 September 2019 (UTC)

utter nonsense
"Games are considered open if the central pawns have been captured, and closed if they have not. Semi-closed games refer to games where some mix of the center pawns have been captured." What ignorant bulls**t; that's not an accurate definition at all. And it just gets worse. Get someone who actually knows something about chess to write this thing, or toss it on the junkpile; as it is, it's worse than useless, and gives the impression that Wikibooks is a joke.
 * Yes, agree about that sentence. How about correcting it yourself? SunCreator (discuss • contribs) 01:33, 22 February 2011 (UTC)

title: Talk:Chess/Strategy


text:
Talk:Asset Allocation

 * See the archives.

Plan
Asset allocation is an important part of investing, and thus a wikibook on the topic should have both instruction and data. Numerous authors have written on the subject (Rick Ferri, William Bernstein, etc.) and citing their recommendations should be fine. Additionally, a large data set should be present here: historical prices and returns for a variety of asset classes, including the stock market, certain components of the stock market (SV, etc.), real estate, international stocks (from various regions), treasuries, bond market, high yield bonds, inflation protected securities, etc. From this data we should have rolling correlation values between all asset classes. I'm suggesting a working plan as follows:

 * Introduction (cite studies showing the power of AA)
 * General information on asset classes and role in a portfolio (i.e. return/risk/correlation, not how each one "works")
 * Domestic stocks
 * International stocks
 * Real estate (including REITS)
 * Government bonds
 * Investment-grade bonds
 * High-yield bonds
 * Precious metals
 * Suggested portfolios (based on various factors)
 * Risk tolerance
 * Appendices
 * Raw data for all asset classes
 * Correlation and return graphs/tables

Feel free to propose changes/discuss. --Spangineer 21:02, 18 July 2006 (UTC)

Raw data sources
Looking for these so that tables can be constructed for return and correlations. So far I've got ; it looks pretty solid. I'm planning to create charts and compare them to previously published charts to ensure their quality, and once that's done, add them here to appropriate pages. --Spangineerwp (háblame)  15:16, 1 August 2006 (UTC)
 * More links: and especially  (French).

title: Talk:Asset Allocation


text:
User talk:DrABomb~enwikibooks

Please see WB:NP in regards to your recent editing. Using root pages is not proper practice. Thanks. -Matt 00:24, 6 January 2006 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called DrABomb. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name DrABomb~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:10, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 04:54, 19 April 2015 (UTC)

title: User talk:DrABomb~enwikibooks


text:
Cookbook talk:Saffron Rice

I am curious about two things: -The saffron rice recipies on the net seem to be asking for way too much saffron. Only a few threads are necessary. -How in the world are you supposed to measure saffron with a half teaspoon? aaron 70.182.5.90 00:37, 6 January 2006 (UTC)

 * Some recipes ask for far too little saffron as a way to cut costs. These recipes often include Cookbook:Turmeric as a way to give a bright yellow color, but the taste is pretty bad. AlbertCahalan 05:38, 14 April 2006 (UTC)

 * You measure it just like you'd measure any other awkward thing. Give it your best effort. You don't need to pack it down. Being off by a large amount is unlikely to ruin the dish; ruining the dish is easily done by making large errors involving salt or the rice itself. AlbertCahalan 05:38, 14 April 2006 (UTC)

title: Cookbook talk:Saffron Rice


text:
Cocoa Programming/Multithreading

Multithreading in Cocoa is just like multithreading in any other *nix application, but there are a couple things you should know.

Not All Cocoa Objects are Thread-Safe
Mutable objects are pretty much not thread-safe, and you should attempt to avoid them and find an immutable alternative. If none exists, you can use locks to synchronize the access mutable objects across threads.

title: Cocoa Programming/Multithreading


text:
Wikijunior:Dinosaurs/Introduction

Introduction
Wikijunior books welcomes you to the Wikijunior book “Dinosaurs”. Dinosaurs were the biggest animals ever to walk this Earth, and their stories excite the imagination of kids of all ages. Dinosaurs have long been extinct, but the creativity of a child is so great that it can be benefited even by learning of a creature that walked the Earth millions of years ago.

The importance of this task has led many experts here at Wikibooks to donate their time and talents to bring this volume together. To learn more about how this book is being created, please see About this book

This book will give you a basic understanding of dinosaurs and some of the events that happened in their time. Of all the creatures that have walked this Earth, few have captured our imagination and fed our desire for knowledge like the dinosaurs have.

One Day Millions Of Years Ago
One day, you are walking through a prehistoric forest, you hear a twig snap behind you. You turn, slowly, hoping that it isn't what you think it is. Standing behind you is a Stegosaurus, chomping away on some leafy ferns. You breathe a sigh of relief. You were afraid it was a predator with its eye on you as a tasty snack. Of course, that was millions of years ago, so it could only happen in your imagination. In fact it was so long ago that there were no people around at all; there weren't even any apes or monkeys yet!

The prehistoric world of the dinosaurs is both strange and exciting. Many things were very different from what you see today. Some dinosaurs stood taller than buildings, and others weighed as much as your entire family put together. Some dinosaurs were small enough to fit in your backpack. Some would not hesitate to eat you on the spot if they were hungry. Others spent all day chomping on ferns and other plants. The one kind of dinosaur that never existed was a dull dinosaur!

There is so much to know about dinosaurs. What is a dinosaur? How is it different from animals today? Are there any dinosaurs living now? Where did dinosaurs live? What did they eat? What did they look like? Why are they gone? How do we know about dinosaurs? Were other animals living at the time of the dinosaurs? How did dinosaurs get their food? Did dinosaurs sleep? How did dinosaurs move? How did dinosaurs protect themselves? Did dinosaurs fight? Could dinosaurs swim? How big was a baby dinosaur? Were dinosaurs poisonous? No matter how long this book is, it could never cover everything there is to know about every dinosaur. If you wish to learn more about dinosaurs, you can find lots of information at the library. You can check out the reference section in the back of the book. You can also visit natural history museums.

Wikijunior Dinosauri/Introduzione

title: Wikijunior:Dinosaurs/Introduction


text:
Muggles' Guide to Harry Potter/Places/Platform 9 and Three Quarters

General Overview
Platform Nine and Three Quarters is a secret platform at King's Cross Station in London. From this location students for Hogwarts are able to catch the Hogwarts Express train. This train runs directly to Hogsmeade Station, close by the school.

Extended Description
Platform Nine and Three Quarters is reached by leaning against, or running through, the barrier between platforms 9 and 10 at King's Cross Station. It is apparently physically located within the confines of the station, though perhaps at a lower level, as the train does seem to pass through an appropriate area of London as it leaves the city. Leaving the platform is generally done by walking through an archway, and a wizard railway guard allows only a few students through at a time to prevent alarming the Muggles when a large number of students appear through a solid brick wall.

The platform has been used in the third, fourth, fifth, and sixth year, as the place for last-minute questions and warnings, as Harry, Ron, and Hermione depart the place they have been through the summer for another year at Hogwarts. In the first year, of course, it was the stage for the initial meeting between the Weasley children then attending Hogwarts (Ron, Fred, George, and Percy), and Harry; it proved inaccessible in the second year due to the well-intentioned but misguided actions of Dobby the house-elf; and as Harry did not attend school in his seventh year, we did not reach this platform. However, Harry visits the platform with his children in the epilogue, and for them, as for Harry in earlier years, it is clearly a place of transition.

Analysis
While the platform might well have been intended to be the place where we change from Muggle to magical life, it has only actually acted as that transition once, in Harry Potter and the Philosopher's Stone. In the other four books where it is a factor, and in Harry Potter and the Chamber of Secrets where it is inaccessible, Harry has been living in the magical world for at least a short time before the trip to the station: three times at The Burrow, once at the Leaky Cauldron in Diagon Alley, and once at Number Twelve, Grimmauld Place.

That is not to say that it is not a transition; in each case, it is a return to school, and thus to a place where Harry's own use of magic is not only permitted, but required. Harry, as an underage wizard, is of course not allowed to use magic anywhere except school. It seems that the largely unsupervised Hogwarts Express is seen as an extension of school, for the purposes of determining whether magic is allowed. Thus, the transition from the repressed world of the underage wizard, to the free world of the wizard who is able to cast spells, seems to happen on the platform.

The reverse transition, of course, happens in the other direction. Stepping off the train and onto Platform Nine and Three Quarters is a return to the world of the underage wizard, a return to the world where magic must be repressed or hidden for fear of frightening the Muggles. We see, in each of the first five books, Harry's reluctance to approach that transition, to return to the unexciting life he perforce must share with the Dursleys.

There is some question, of course, as to why so many students travel on the Express. London is in the south of mainland Britain, and Hogwarts is in the north. Would it not make sense for students who live further to the north, like Seamus Finnigan, who is apparently Irish (although we don't know where he lives over the summer), to travel directly to Hogwarts, rather than detouring far to the south of Britain to London and then heading further north to Scotland? This question is never addressed, though it may be worth pointing out that a lot of the British rail network is what is called a "hub and spoke" topology. For reasons dating back to the early days of the railroads, it seems that almost all railroads run to or from one of the several London stations, with relatively few interconnections. It may be simpler to connect with the Express in London than to try and find a train that runs in a more direct manner, particularly since Hogsmeade, as an all-magical village, likely does not appear on many rail schedules.

It is mentioned on the Pottermore web site that travel on the Hogwarts Express has been mandated by Wizarding law, in order to prevent mass migration of students at the start and end of the school year, and use of more dangerous means of transportation. No suggestion is made as to why mass migration to London at the same times is considered less alarming to the Muggles.

Greater Picture
In the seventh and final book, of course, Harry does not attend school, and so the transition from Muggle to Wizarding worlds does not occur. However, in the opening chapters of that book, Harry reaches his seventeenth birthday and comes of age. At this point, he is allowed to do magic on his own, and so the transition from repression to encouragement of magic does not require boarding the Hogwarts Express. As he has also left the Dursley house for the last time, there have already been fairly major transitions, so adding another one would be superfluous.


text:
User talk:69.106.56.6

Thanks for experimenting with Wikibooks. Your test worked, and has now been removed. Please use Sandbox for any other tests you want to do, since testing material in modules will normally be removed quickly. Please see the welcome page if you would like to learn more about contributing to our project. Thanks. Guanaco 03:58, 6 January 2006 (UTC)

title: User talk:69.106.56.6


text:
Wikijunior talk:Dinosaurs/Introduction

Poorly Written
I wrote it, and I realize this. Something needs to be done to it, and it needs to be expanded in some way. I was thinking of including a short little story making it fun while being informative, but I didn't have time, I will return though. Like it says on the cover discusion page, nothing is sacred rip, tear, rewrite, and edit the heck out of everything. We don't even have a rough draft done right now! The book is just a collection of thoughts, and the research isn't done. So, if anyone has any Ideas for the introduction, may you edit in peace.

After several rewrites
Still poorly written, but I believe its better. I stole a section of it out of Wikijunior's Big Cats, but just because I like the forward alot. Still, I don't think it shows enough...of something, but I am lost for what it needs, if anyone out there see the missing link, please fill it in.

Bias
This module appears highly biased. Educational material should at least inform the reader that a controversy exists. I'm talking mostly about the origin of life and how old it is.

How would someone counter an argument from the "opposition" if they don't even know the view point exists?

 * Note that not only is this wikibook not complete, it is also not all inclusive. If you feel that the book needs a bit of information or another section, create it, or discus it in a friendly mannor on the discussion page.  Please note that no one and no group of people will ever enjoy being called biased, no matter wether or not how true it might be.  Secondly, your comment seems to sugest that the science comunity is torn apart by this issue, which is plainly not true.  Few scientists agree with the intelligent design, and most with evolution and the idea that the earth is very old.  No matter what you say, that is true.  One of the great things about the spirit of free knowledge and free inquiry that wikipedia and wikibooks provides you however is that it does not require that you agree with the majority.  I think if enough people are going to be offended by the lack of an alternitive mentioned in this book, then write a section, let future readers of this book know of an alternative that exists in this world to the facts and information they are being given.  You must face the cold hard reality of the magority, and the cold hard reality presented by the facts.  If one day scientists prove that an intelligent being created the world, I will be happy, for science would have triumphed and our knowledge of the world would be one bit more complete.  Until that day, I will stick with that which seems moost likely, and has had the most evidence, and the most backing.--Pampaeditor 22:42, 12 January 2006 (UTC)
 * I think the anyonamous author above is reffering to the creation-darwin "contoversy" which has mostly vanished in the last century. This is not valid here. The scientific facts here are what must be accepted. WikiMedia is not a religious institution and therefore the views of a certain group must not be represented over those as another. Creationisim can be discussed in another book, but here, where the dinosaurs are the subject matter, one must assume that they existed if one wishes to write about them.

--Basejumper123 00:15, 7 February 2006 (UTC)

 * Anonymous poster, the only "controversy" is entirely generated by religious hacks, 99% of whom don't have any formal education in biology, geology, or paleontology. Their ignorance does not constitute evidence, nor does it make for a very good argument. 68.127.123.197 (talk) 22:30, 23 February 2008 (UTC)

TO ALL CONTRIBUTORS: Please Sign your Talk!

Another bias I noticed is in the statement, "Dinosaurs were the greatest beings to ever walk this Earth." Saying "greatest" violates the NPOV policy. Could we please be more specific? --Gray Porpoise 01:07, 14 August 2006 (UTC)
 * "Dinosaurs were the largest creatures known to have walked the earth"? I think that might be what the author meant, but it doesn't convey the fact that dinosaurs varied greatly in size. 68.127.123.197 (talk) 22:30, 23 February 2008 (UTC)

Editing
I am making some small edits to make the flow of the Intro more real, sincere, and less chopy. The content included is good and it states all the right ideas, but it is in need of a non-author editor. I would encourage each and every person on the project to take a look themselves! P.S. The spelling in this article is completely correct as of my edit at the time below

--Basejumper123 01:24, 7 February 2006 (UTC)

You hear a twig snap
Sure it's a nice line, grabs attention. But it also reinforces the myth that humans and dinosaurs have coexisted. I've added a bit about "it could only happen in your imagination" to counter that. 203.22.236.14 09:23, 20 February 2006 (UTC)
 * Or write it explicitly from the POV of another dinosaur. 68.127.123.197 (talk) 22:31, 23 February 2008 (UTC)

Some ideas
Eugh! I know what you mean! Paleontology can't be an easy topic to discuss with juniors in a meaningful way. I have a dreadful book aimed at kids which starts off "Dinosaurs were a group of really successful, land-dwelling creatures that dominated Earth bewteen X million and Y million years ago." Really! It must be hard for a paleontologist to talk to children. I have just typed in what I told my five-year-old, 8 lines. Hope it's religiously inclusive enough for you all (heh heh). I'm NOT going to change a word of what you put in your introduction because my description is aimed at younger people, but if you see anything you like cut and paste - it's my own work, you can have it.

"For thousands of years - since before the first history books - people have been digging things up out of the ground.

Here are some of the things we dig up: amber, for jewellery, flint, for arrows; clay, for making pots; Slate for roof tiles; chalk for drawing; peat, which burns easily in fires and so on.

Now, some rocks come from volcanoes when they spit out globs of molten rock, which cools down and goes hard. No volcanic rocks contain bones (but they might have diamonds in them!). Another way rocks are made is by being built up over time --  by layer upon layer of mud and sand from a river that floods from time to time. The lower levels can be very hard. Slate, for example, is a type of stone made from compressed mud. With these rocks, the deeper you dig, the older the mud that you are digging up. These types of rock sometimes contain the skeleton of an animal that has been buried in the mud.

From time to time people would dig up big - and I mean REALLY big bones. When this happened, it caused a bit of a problem for the people that wanted to know what animal the bone came from, because we know about all the animals that live in the world today and there aren't any with bones that big. Judging by how deep they were, they must have been from a long time ago.

People came up with ideas to explain how it could be that you can a) have bones and b) not have any animals with those bones. Here are some explanations people came up with: that there was an enormous flood that drowned nearly all the creatures on Earth, and all the creatures alive today have descended from the ones that escaped the flood. Another idea was they are the bones of dragons - gigantic and powerful reptiles[1].

As time went on, more and more of the bones have been unearthed and we have now got a lot of skeletons. We have also learned how to tell exactly how old they are, and when we arrange them in date order we have a fossil record that shows how 'modern' dinosaurs evolved from 'primitive' dinosaurs. We have also found winged, feathered dinosaurs, which look like they could have been distant relatives of birds today.

One day, about sixty-five million years ago, something happened and now the dinosaurs are all dead. Nobody is quite sure what happened, but the rock at that depth has a lot of soot in it. You can find dinosaur bones below that line, but you never see any above the line. Most people think that there was a huge disaster that caused a lot of fires and changed the Earth's climate so the dinosaurs died out. Nobody really knows for sure, but it could have been caused by an asteroid hitting the Earth. We do know that very large asteroid hit the Earth around the time the dinosaurs died out and the crater it left behind is 180 km or 112 Miles across[2].

We also sometimes find the bones of people (human remains). The oldest human remains are about 100,000 years old[3], which is much less than 65 million years, so at no time has a human ever met a dinosaur."

[1] http://en.wikipedia.org/wiki/Dragon#Speculation_on_the_origin_of_dragons

[2] http://en.wikipedia.org/wiki/K-t_boundary

[3] http://en.wikipedia.org/wiki/Human#Origin

PS. Tend to agree with the comment about the twig snapping - you'll need a time machine if you want to keep it with a person in it. -- M-streeter97

title: Wikijunior talk:Dinosaurs/Introduction


text:
Wikijunior talk:Dinosaurs/Tyrannosaurus

Reference List
This It the T-Rex Reference list, please place all references here
 * 1) []
 * 2) []
 * 3) []

Photo List
This is the Photo Reference List Place all Useable Photo Links HERE
 * image:T-Rex_Head.jpg
 * image:Saurier2.jpg
 * image:Trex skelleton 2.jpg
 * image:Palais de la Decouverte Tyrannosaurus rex p1050042.jpg
 * image:T-Rex Skull.jpg

Reads acwardly and is shallow
Prose needs to be cleaned up, and it needs more depth.
 * please sign talk! this is how you make the link "User:Username|Username" thanks Basejumper123

Humility
Agreed. By Pampaeditor Jan 7.

When to abbreviate?
We really need to decide when to say the cute name and when to use the full one. Do we introduce the short one and say "let's just call him T-Rex" and use it afterwards, or should the full name lead each section before reverting the the short name once more? GarrettTalk 01:09, 9 January 2006 (UTC)

Factoids
Would it be possible to create a list of interesting facts (on this page, perhaps) that should probably be worked into the text? For instance, I remember being fairly impressed as a kid that T Rex's estimated running speed was 35 miles per hour. I remember there being numerous other things like this that can give a 'wow' factor or help put size and power in modern context. N Vale 19:47, 22 January 2006 (UTC)

T, Rex
Rather than a hypen we should use a Period. Cause T stands for something. N1person 18:12, 28 January 2006 (UTC)

 * Hm, well, I disagree. The hypen has been used so long and so widely, if we did otherwise we'd merely end up explaining why we'd changed it in the first place. GarrettTalk 07:05, 29 January 2006 (UTC)

 * I see no problem with having breif grammer lesson in the book. :) N1person 03:52, 5 February 2006 (UTC)

 * I think Garrett is right its really more understandable for young kids just to use the hyphen especially because Tyranasaurus is not really in their vocab. Basejumper123 22:47 6 February, 2006

"T. rex" is correct, though. Giving incorrect imformation is a type of vandalising. Dora Nichov 12:24, 28 August 2006 (UTC)

T-Rex
The T-Rex page now appears unreadable in my opinion. It looks like the sentences are ending all over the place. Young Kids will take one look at this and see A LOT of T.'s whoever put that in please change it —Basejumper123

Ive done my edit on whats already been written! --Basejumper123 23:18, 6 February 2006 (UTC)

Great project! Made some corrections
I just recently found this project. I am thrilled that a project aimed at children is underway. As a homeschool mom with 9 and 4yo boys, I see a lot of potential here. I do not see that potential being fully realized, but I am sure it will eventually mature. I am hoping to jump in and become an active participant.

As for this page, I went and corrected some spelling errors. There is also the inconsistency with the two different abbreviation conventions (T-rex and T.rex). I can see the discussion already going on about it. T-rex is what children will recognize. I did not want to change the T.s if there is still a question, but if nobody objects I will be happy to make it consistently T-rex.

My 9yo has volunteered to be a test reader. He is a gifted kid with very high reading ability, but he is good at identifying what will be appropriate for "normal" 9yo's. I will pass along his comments.

Starchildmom 09:39, 29 March 2006 (UTC)

About the size of the eyes
The article says that "Their bodies could easily be spotted by their forward lean, their short but deep jaws, their huge teeth, large eyes, long tail, and tiny arms" but also that "Due to their small eyes--". So does the T-rex have small or large eyes? -80.220.34.82 13:53, 27 June 2006 (UTC)

 * Thanks for pointing out, and sorry for the slow response (Wikijunior Dinosaurs are rather inactive now). I am not certain what the original authors meant, but I have rephrased these parts - should be clearer now.--Konstable 08:32, 4 July 2006 (UTC)

Life skills
Calf Mamello Mosia (discuss • contribs) 08:04, 24 February 2021 (UTC)

title: Wikijunior talk:Dinosaurs/Tyrannosaurus


text:
Talk:Biblical Studies/Christianity/Prayer

Debts, sins, or trespasses
The paraphrase "trespasses" is consistent with the succeeding verses 14 and 15 in the King James and the Church of England BCP, where it seems to mean offences. Trespasses goes with the flow as well. - Athrash | T a l k 05:10, 6 January 2006 (UTC)


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General Astronomy/The Big Picture

The universe is a big place — too big for us to comprehend. But how big? Astronomers have struggled with this question for millennia, and their view of the known universe has steadily grown to immense and incomprehensible sizes. It’s an important question, and a basic part of our grasp of the universe itself. To study astronomy, it’s essential to understand what’s out there, how everything relates, and where we fit in the universe. The problem is that the size scales, the relative general sizes of classes of objects, are too foreign for things much larger than Earth. In a big universe, this can be a challenge. To tackle the problem, let's try to connect the familiar life-size world around us with the unfamiliar cosmic size scales.

If you're a student, you probably watch your instructor write on the chalkboard almost every day. The chalkboard is something you're much more familiar with than the whole universe because you can see it and touch it. You know the size of the board, the chalk, the markings, the eraser, and so on because they’re right at hand. How much bigger is the board than a dot made on the board with a piece of chalk? It turns out that the answer is about a thousand, for an average sized chalkboard, and a fair sized chalk dot.

Now let's consider something that's a thousand times the size of a blackboard. A blackboard is a few meters across, so we want to think about something a few kilometers across. That's something like the size of a small city. If a city is 1000 times larger than a chalkboard and a chalkboard is 1000 times larger than the mark on a chalkboard, that's a useful connection that helps us think about the size of a city: we can say that the chalkboard in the city is like the mark on the chalkboard.

In this way we will now step out from the city into the larger universe. With each step, we will consider something (very roughly) a thousand times larger than the last step. As we move out, each stop in our journey will be much smaller than the next, like a mark on a chalkboard.

A city is much larger than the blackboard we used as a reference point, but it's still something we are very familiar with. Many people drive across part of their home city and back again every day. It's possible to drive through most small cities in a half hour or so, even with stoplights, and it only takes a few hours to walk from one end to the other. As promised, the next step out will be much larger and farther from our everyday experience. Our next stop will have a size of several thousand kilometers, and that's the size of Earth.

In a car, you can drive across a city in less than an hour, even at a slow speed. If you could drive around the Earth at a speed of 60 miles per hour (100 kilometers per hour), going day and night over land and water, it would take a full 17 days. Remember, driving through a small city at 60 miles per hour would only take a few minutes. Seventeen days is much, much longer than a few minutes. The fastest jets, which have a top speed of about 2,000 mi per hour, can make the trip around the world much faster. At that speed, you could circle the Earth in 11 hours. Even speeds like that will quickly become inadequate as we continue moving out into the universe.

The size of Earth is typical of the sizes of the rocky planets, the terrestrial planets, but planets made mostly of gas such as Jupiter and Saturn are larger by a factor of several to ten. In general, we can expect the same kinds of things to have similar properties. Given no other information about a planet, we might guess its radius to be the same as Earth's. If we knew that our imaginary planet were a much larger gas giant, we might change our estimate and guess that the planet has the same radius as say, Saturn.

This size scale represents the vast majority of human experience. Only a small number of people have ever been in Earth orbit, and these people remained very close to Earth. Most of the satellites launched remain very close to Earth. The shuttle, for example, orbits at an altitude of only a few hundred kilometers — a few percent of the radius of Earth. Some spacecraft are sent to other planets or to the Moon, but the majority stay at the scale of this step in our journey. Only 24 people — the Apollo astronauts — have ever left Earth's orbit to visit the next stop on our journey.

As we continue to move out, we reach a size of about 1000 times the distance around the Earth. The distance to the Moon is about 30 times the diameter of Earth, so the Moon is easily within reach in this step, but there's little else in the remaining distance. The nearest planets, Mars and Venus, are out of our reach. Aside from the Earth and Moon, we find the space in the neighborhood of Earth to be almost completely empty, with only the occasional passage of an asteroid or comet.

Although the Moon seems nearby when we consider the huge space surrounding the Earth-Moon system, we should remember that the Earth and Moon are really very far apart. If we could get in a car and drive to the Moon, the trip would take five months of driving nonstop — 24 hours a day and seven days a week. If our jet could go to the Moon, it would take five days to get there. These trips are becoming longer now, but they're still manageable. The trip by foot is much longer, though — a walk to the Moon would take nine years! Light travels faster than anything else in the universe. It has a speed of 300,000 km per second. At this speed, light can travel to the Moon in just over one second. This distance, the distance light travels in one second, is called a light-second.

Another step out will extend our reach to most of the planets. We now encompass the bulk of the Solar System, the system comprising the Sun and all of the objects orbiting around it. This size scale is about five billion kilometers across, 30 times the distance between the Earth and the Sun. The distance from the Earth to the Sun is a convenient standard for measurement in the Solar System, so astronomers use the average Earth-Sun distance as a standard unit called the astronomical unit (AU). One astronomical unit is equal to about 93 million miles or 150 million kilometers. We can say that we are now working at a size scale of 30 astronomical units, or 30 AU for short. A box this size centered on the Earth would comfortably fit Saturn's orbit, but Uranus, Neptune and Pluto are still too far away. For much of human history, none of the Solar System objects outside of this box were known to exist.

Remember that our size scale has increased from the last step by a huge factor, a factor of 1000. Using our jet to take a trip from Earth to Saturn would take about fifty years. Light takes about 80 minutes to travel from Saturn to Earth, depending on where Earth and Saturn are in their orbits. Because it takes so long for light to make the trip from Saturn, the light we see from the planet at a given moment actually left 80 minutes ago. This means that we don't see Saturn as it is presently, but as it was 80 minutes ago. This also means that looking out into space is like looking back in time. The farther we look, the older the light. This is not very important for Saturn, but it will become more important as the size scale increases.

As before, we can use the speed of light as a measure of distance. A light-second is the distance light travels in one second. Likewise, a light-minute is the distance light travels in one minute. That means that Saturn is 80 light-minutes away. In the same way, we could write that Saturn is 1.3 light-hours away, and that's about the same as Saturn's distance from the Sun. Saturn's orbit is much bigger than Earth's orbit, which is only 8 light-minutes in radius. This is a striking and important fact about the Solar System — the rocky planets, the terrestrial planets, orbit close to the Sun and close to each other, but the giant gas planets, the Jovian planets, orbit at greater distances and have more widely spaced orbits.

The next step in our journey will encompass a distance of 30,000 AU, or half a light-year. Although this step completely encloses the planets, Solar System objects are found at much greater distances. These objects form the Oort cloud — a vast, sparse region of comets surrounding the Sun. The Oort cloud is almost empty, but it's there just the same. At this step we've only covered a piece of the range of influence of the Sun, and plenty of Oort cloud remains out of our reach. The Oort cloud is thought to extend out from the Sun as much as two light-years.

If we look just beyond this step, we find the nearest star, Proxima Centauri, at about four light-years. It will take Voyager 1 and 2 80,000 years to reach this star. (These ships, launched in 1977, have a speed of 51,500 km/hour.) As other stars enter into the picture, the Sun will no longer be the dominant source of gravity. This means that we can expect the solar system to really end as we begin approaching other stars.

Our next step out places us in a 500 light-year box. This size scale is easily large enough to fit the Sun, Alpha Centauri, and many other stars. In fact, about 250,000 stars are within 500 light-years of Earth. Astronomers refer to this region as the Solar Neighborhood. As we've seen, the stars in the Milky Way are very far apart, with vast stretches of mostly empty space separating them.

Stars in the Solar Neighborhood (and throughout space) are mostly small and faint. If these fainter stars were much farther away, they would be too faint to see from Earth. Much brighter stars are more rare, but they can be seen from much farther away. Because of this, two "kinds" of stars fill the sky as viewed from Earth: stars that are intrinsically faint but nearby, and stars that are bright and more distant.

As we continue outward in our journey, we see the random scattering of stars form into a pattern. Spiral structure emerges, and we see that the Earth, the Solar System, and nearby stars are collected together into an orderly system of stars called a galaxy. Our galaxy is called the Milky Way Galaxy.

Like the Solar System, the Galaxy is shaped like a flat disk, but the Galaxy is much bigger. Our galaxy contains hundreds of billions of stars, and the Solar System is only one member contained inside. The Sun is located in the spiral arms of the galaxy about two thirds of the way from the center, and it orbits around the center of the galaxy with all the other stars. If the Milky Way were fifty miles long, the Solar System would only be a dot the size of the tip of a ball point pen. In actuality, the Galaxy is 100,000 light-years across, but only a few thousand light-years thick.

As we start out towards the next step, we see other galaxies like the Milky Way begin to appear. Compared to stars in the Milky Way, galaxies are packed together much more closely, and collisions between galaxies are much more common. The Andromeda Galaxy, the nearest galaxy to the Milky Way, is 2.5 million light-years away and on a collision course for Earth. Don't panic, though, as the collision won't happen for another 3 billion years.

At a size scale not much larger than our last, we see that the galaxies are clumped together. These galaxy clusters typically have hundreds of galaxies and are millions of light years across. Galaxies orbit around the center of their clusters. The Milky Way is a member of the Virgo Cluster. It orbits near the edge of the Cluster, so we can see much of its center in a small region of the sky in the direction of the constellation Virgo. Presently, the Milky Way is moving away from the center of the Virgo Cluster. In the distant future, however, the Cluster's pull will slow the Milky Way and draw it inward.

Although our reach now includes many more objects, the size scale of galaxy clusters still does not represent an expansion over the last size scale by a factor of 1000. We have not fully reached the next step in our journey until we come to the scale of hundreds of millions of light years. At this scale, even the galaxy clusters form clusters. These groups of galaxy clusters are called superclusters. A supercluster may contain hundreds of thousands of galaxies. The Virgo Cluster is a member of a supercluster called the Virgo Supercluster.

Light from the edge of our 500 million light-year reach has traveled for 500 million years before reaching us. This means that we see the Virgo Supercluster as it was 500 million years ago. Five hundred million years can be a long time, but it isn't really long enough for the universe to have changed significantly. Even though the light is old, the universe at the edge of the Virgo Supercluster still looks much like the universe nearby.

As we continue out from the 500 million light-year size scale, we see older and older parts of the universe. As the distance becomes very large, we begin seeing billions of years into the past, and big changes in the Universe as a whole become important. Going further and further back, we see the formation of the first galaxy clusters, galaxies, and stars. Eventually, we see the universe so young that no stars have formed yet. Before the first stars formed, the Universe was cool and dense enough for the loose, unused gas in space to block visible light. Beyond this, we can't see any further. The contents inside this wall are called the Hubble volume, or the Observable Universe. There's no way to observe objects outside of this volume because the light from these distant objects hasn't reached us yet.

The Universe extends out infinitely, but our view is limited to the Hubble volume. Trying to visit the edge of the Hubble volume is impossible. You'll never reach it because it's only an illusion. If you tried to visit the location where we see the edge of the Hubble volume, you would see the universe around you as it is today, not billions of years ago, and you would see the edge of the Hubble volume all around you, billions of light years away.

Extending out further inevitably delves into the pages of theory and crosses the line dividing what we have seen and what we cannot see. Some have theorised that the universe itself does not comprise all of existence, and that there may be other universes with different physical laws existing together in clusters and groups in a multiverse.

As we go further and further out, many note that there must be an edge, an end, a border of reality. Others have speculated that the universe, or the multiverse it sits in, is simply infinite, and has no such boundaries. However, at this point in time, there can be no absolution, no definite answer to these questions.

Much remains unknown about what the Universe is like, but our picture has evolved dramatically since humanity first began asking questions about the world around it. Armed with curiosity and the tools of science, astronomers have investigated the heavens for centuries, and their work continues today.

title: General Astronomy/The Big Picture


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Introduction to Psychology/Intelligence

Intelligence
The concept of intelligence is, in many ways, culturally bound. Not all languages or cultural groups have a word equivalent to "intelligence;" to cultures in which academic work and achievement are unimportant, the idea of "intelligence" is moot.

IQ
In 1904, the French Ministry of Education asked Alfred Binet to come up with a way to identify children who would need remedial help with schoolwork. They wanted to identify these children as early as possible. In 1912, William Stern developed a formula often misattributed to Binet or Lewis Terman to capture the essence of Binet's work: Intelligence Quotient = Mental Age/Chronological Age x 100. This is typically written: IQ = MA/CA X 100. In other words, if a child of 6 years (CA) is achieving at the same level as his 6-year-old peers (MA), his IQ = 6/6 x 100, or 100. For this reason, the score of 100 became the "average" IQ, and remains so today.

Theories of Intelligence
Since Binet, psychologists have gone back and forth between believing intelligence is one thing and believing it consists of many talents or intelligences. Many of the most reliable modern intelligence tests are based on the idea of intelligence as one thing (in keeping with Binet's original mission, typically something that is highly correlated with academic achievement), but proponents of multiple intelligences argue that

The Bell Curve
the testing of iq

Herrnstein and Murray's Bell Curve
Back to Table of Contents << Previous chapter||Next chapter >>

title: Introduction to Psychology/Intelligence


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Using an Abacus/Addition

Addition
Addition is thought to be the easiest function the abacus can calculate. To add, the user must display the original number and add the desired number of beads to the original number.

Example: (6+5) 6=6 0000-|-0 (0) 000-0|0-  (6) 6+5=11 000-0|-0  (1) 000-0|-0  (1)

title: Using an Abacus/Addition


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Using an Abacus/Subtraction

Subtraction
Subtraction is the second most basic function of the abacus. The subract, the user displays the original number and takes away the desired amount of beads from the original number.

Example: (12-4) 12=12 000-0|-0 (1) 00-00|-0  (2) 12-4=8 0000-|-0  (0) 0-000|0-  (8)

title: Using an Abacus/Subtraction


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Using an Abacus/Multiplication

Multiplication is, by definition, the addition of some number so many amount of times. Therefore, to multiply a number by a desired number requires the same principle.

To multiply:
 * 1) Display the original number.
 * 2) Think of desired multiplier.
 * 3) If multiplier has more than one digit, multiply by digits separately
 * 4) Add the original number however many times desired.
 * 5) Move to the next digit and repeat step 4 if multiplier has more than one digit.

Example: (4×5) 4=4 0000-|-0 -0000|-0 4+4=4×2=8 0000-|-0 0-000|0- 8+4=4×3=12 000-0|-0 00-00|-0 12+4=4×4=16 000-0|-0 000-0|0- 16+4=4×5=20 00-00|-0 0000-|-0

Here is another example with one number having two digits: (5×2.5)

5=5 0000-|-0  (0) 0000-|0-   (5) 0000-|-0• (.0) 5×2=10 000-0|-0 0000-|-0 0000-|-0•

5×0.5=2.5 0000-|-0 00-00|-0 0000-|0-•

10+2.5=12.5=5×2.5 000-0|-0 00-00|-0 0000-|0-•

title: Using an Abacus/Multiplication


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Using an Abacus/Division

Division is practically the opposite process of multiplication. Division of a given number by a desired number involves the subtraction of the given number by the desired number a certain amount of times, and this certain amount of times the answer.

To divide:
 * 1) display original number
 * 2) think of desired number
 * 3) subtract original number by desired number
 * 4) add a bead to a separated row (recommended two above highest digit of original number), this is the counter row
 * 5) Repeat steps 3-4 until original number is less than desired number
 * 6) multiply original number by 10 and repeat steps 3-4 while adding one bead one digit less than counter.

Example: (15/4) 15=15     Counter 000-0|-0  0000-|-0 0000-|0-   0000-|-0• 15-4=11    1 000-0|-0   000-0|-0 000-0|-0   0000-|-0•

11-4=7    2 0000-|-0   00-00|-0 00-00|0-   0000-|-0• 7-4=3      3 0000-|-0   0-000|-0 0-000|-0   0000-|-0•

30-4=26   3.1 00-00|-0   0-000|-0 000-0|0-   000-0|-0• ... (6 more times) 6-4=2     3.7 0000-|-0   0-000|-0 00-00|-0   00-00|0-•

20-4=16   3.71 000-0|-0   0-000|-0 000-0|0-   00-00|0-•            000-0|-0 ... (4 more times) 4-4=0     3.75 0000-|-0   0-000|-0 0000-|-0   00-00|0-            0000-|0- Thus (15/4)=3.75

title: Using an Abacus/Division


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Wikijunior:Dinosaurs/Authors

If you wish to be formally listed as an author of Wikijunior Dinosaurs, please sign your name below.

According to the United States Code for registering a copyrighted work, you must include your nationality (what country you claim citizenship in) and the country you are currently residing in, if different. It is also suggested by the U.S. Copyright office to include the year you were born, for identification purposes. They also ask for the year of death, and if you know of a Wikibookian who has passed away, this would also be useful. How exactly we are going to collect this information for users and contributors of this Wikibooks is totally unknown, and is going to be an interesting little ride. Please add comments in the discussion page if you have any reservations about giving this information out. This is moving into new territory here, so we don't know exactly what is going to be required or if new policies should or ought to be developed.

Keep in mind, this information is needed only if you want to be credited formally as the author of this Wikibook and have your information correctly cited in any formal registration procedure for this Wikibook. Efforts to get this information put into the general user record of MediaWiki have met with huge resistance even on a voluntary basis, so this is the only forum for you to even put this sort of information out to the public. This information may also be needed for enforcement of copyright laws in the unfortunate situation where somebody copies this Wikibook contrary to the terms of the GFDL. An attempt to contact you would then be done to see if you would be willing to enforce your copyright for this Wikibook.

Anonymous authors include those who made edits without logging in as a user. While edits of this nature are appreciated, there is no way we can give attribution to any specific person unless they have created an account here.

Authors

 * 1) Robert Horning, Logan, UT, USA
 * 2) Weebs
 * 3) Wjbean
 * 4) Pampaeditor, Pampa, TX, USA
 * 5) EuropracBHIT, Melbourne, Victoria, Australia.
 * 6) Basejumper123,(Benjamin Mitchell) Massachusetts, USA
 * 7) Konstable, Auckland, New Zealand
 * 8) KunalThaggarse, Pune, India
 * 9) User:Bart133, Nevada, USA
 * 10) Matthew J., Homewood, IL, USA
 * 11) DinoBird, Dinosaur Expert
 * 12) Scienciac
 * 13) ArrieAnna T., Michigan
 * 14) Teh1337 (talk), USA
 * 15) Aryaman Arora, Savannah, GA, USA
 * 16) Sethysaurus, England

title: Wikijunior:Dinosaurs/Authors


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User talk:Shotgunlee

AK-47 Instruction Manual
Welcome to Wikibooks. I hope that you enjoy your experience while you are here.

I've noticed that you've started a new Wikibook here called AK-47 Instruction Manual. Make sure that you try to expand this into something that really resembles a manual and not just a simple encyclopedia article. I know that this is right at the beginning thoughts on how to do this, so I am willing to offer you some suggestions and pointers.

If you want to look at some successful Wikibooks and try to see how they are formatted, you might want to look at Book of the month for a list of some of the best ones here. You can copy stuff from Wikipedia as the foundation and initial core of content here, but it would be suggested that you substantially expand the content once you bring it to Wikibooks. That process is especially recommended if you are trying to cut a Wikipedia article down due to the length of that article.

Good luck on this project, and I hope it proves to be successful. --Rob Horning 14:36, 6 January 2006 (UTC)

 * Thank you for your attention. However, I started the AK-47 Instruction Manual merely because the operation section of AK-47 article in en.wikipedia was removed by somebody (not me!) due to wikipedia policy, which says that wikipedia is not instruction manual. I thought that it would be good to preserve the removed content for future use, so I copied it to here.

 * Sadly, I don't have enough knowledge for AK-47. I just hoped that someone else will expand that small section to a real manual. -- Shotgunlee 06:38, 7 January 2006 (UTC)

title: User talk:Shotgunlee


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User:Samw

See Wikipedia:User:Samw

title: User:Samw


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High School Physics/Projectile motion

The case of uniform gravity, disregarding drag and wind, yields a projectile motion trajectory which is a parabola. To model this, one chooses $$V = m g z$$, where $$g$$ (gee) is the so-called acceleration of gravity.

Relative to a flat terrain, let the initial horizontal speed be $$v_h$$, and the initial vertical speed be $$v_v$$. It will be shown that, the range is $$2v_h v_v/g$$, and the maximum altitude is $${v_v^2}/2g$$. The maximum range, for a given total initial speed $$v$$, is obtained when $$v_h=v_v$$, i.e. the initial angle is 45 degrees. This range is $$v^2/g$$, and the maximum altitude at the maximum range is a quarter of that.

Derivation
The equations of motion may be used to calculate the characteristics of the trajectory.

Let:
 * $$t \;$$ be the time into the flight of the projectile
 * $$d_h(t) \;$$ be the horizontal displacement at time t
 * $$d_v(t) = z \;$$ be the vertical displacement at time t
 * $$v_h \;$$ be the horizontal velocity (which is constant)
 * $$v_v \;$$ be the initial vertical velocity upwards
 * $$v \;$$ be the initial speed
 * $$v_v(t) \;$$ be the vertical velocity at time t

Along the horizontal dimension, $$v_h$$ is a constant and thus by the equations of motion,
 * $$d_h(t)=v_h t \;$$ (Equation 1)

The vertical distance, or altitude, follows the equations of motion for constant negative acceleration $$g$$:
 * $$d_v=v_vt- {{gt^2} \over 2}$$ (Equation 2)
 * $$v_v = \frac{d}{dt} d_v(t) = v_v-gt$$ (Equation 3: velocity equation which is the derivative of equation 2)

The range of the projectile occurs when $$d_v(t)$$ is zero again and intercepts the ground. This occurs when $$d_v$$ in equation 2 is zero:
 * $$0=v_vt- {{gt^2} \over 2 }$$

Solving this for time $$t$$ gives the time of the projectile's flight:
 * $$t={2v_v \over g }$$ (Equation 4: "hang time" of projectile)

The maximum range occurs when equation 4 is substituted into equation 1:
 * $$d_h(t) = { v_h t } = { v_h ({2 v_v \over g})} = { {2 v_h v_v} \over g } $$ (Equation 5: range of projectile)

The maximum altitude for a given trajectory occurs when the vertical velocity is zero. Thus set equation 3 to zero:
 * $$0=v_v-gt \;$$

Solving for $$t$$
 * $$t= { {v_v} \over g } $$

This can be substituted into equation 2 to give the maximum altitude:
 * $$d_v(max)=v_v ( {v_v \over g}) - \frac 1 2 g( { v_v \over g } )^2 = {{v_v}^2  \over 2g } $$ (Equation 6:  maximum altitude of projectile)

Thus, not surprisingly, for a given initial speed the attained altitude is highest if the initial velocity was straight up. This altitude is twice the attained altitude when the range is maximized.

Derivation in polar coordinates
In terms of angle of elevation $$\theta$$ and initial speed $$v$$:
 * $$v = \sqrt{ {v_h}^2 + {v_v}^2 } $$
 * $$v_h=v \cos \theta \;$$
 * $$v_v=v \sin \theta \;$$

Substituting into Equation 1 gives:
 * $$d_h=v_h t = vt \cos \theta \;$$ (Equation 1a)

Substituting into Equation 2 gives:
 * $$d_v=v_vt- {{gt^2} \over 2} = ( v \sin \theta ) t - { { g t^2 } \over 2 } $$ (Equation 2a)

Taking the derivative gives the vertical velocity:
 * $$v_v=\frac{d}{dt} d_v = \frac{d}{dt} (v \sin \theta) t - {{g t^2} \over 2} = v \sin \theta -gt $$ (Equation 3a: vertical velocity)

Hang time calculated above in equation 4 may be expressed in terms of angle of elevation:
 * $$t={2v_v \over g} = {{2 v \sin \theta } \over g }$$ (Equation 4a)

Equation 4a may be substituted into Equation 1a to get the horizontal distance or range:
 * $$d_h=v_h t = { vt \cos \theta } =v ({{2 v \sin \theta} \over g}) \cos \theta = { { 2 v^2 \sin \theta \cos \theta } \over g}$$

Now using the trigonometric identity for $$2 \sin \theta \cos \theta = sin 2 \theta$$:
 * $$d_h={{ v^2 \sin 2 \theta } \over g}$$ (Equation 5a: range of projectile)

This may be solved for angle $$\theta$$ to give the "angle" equation to hit a target at range $$d_h$$:
 * $$ { \theta } = \frac 1 2 \sin^{-1} ( { {g d_h} \over { v^2 } } ) $$ (Equation 7: angle of projectile launch)

Note that the sine function is such that there are two solutions for $$\theta$$ for a given range $$d_h$$. Physically, this corresponds to a direct shot versus a mortar shot up and over obstacles to the target.

The maximum altitude for a given range may be determined by setting the vertical velocity to zero in equation 3a and solving for $$t$$:
 * $$0= v \sin \theta -gt \;$$
 * $$t= \frac{v \sin \theta}{g} $$ (rearrange and solve for $$t$$)

Now substitute into the vertical height equation 2a:
 * $$d_v = (v \sin \theta) t - \frac{g t^2}{2} = (v \sin \theta)(\frac {v \sin \theta}{g}) - \frac {g (\frac{v \sin \theta}{g})^2}{2} = \frac{v^2 {\sin}^2 \theta}{g} - \frac{v^2 {\sin}^2 \theta}{2g} = \frac{v^2 {\sin}^2 \theta}{2g}$$ (Equation 6a: max altitude for a given launch angle)

Maximum range
Given the above range and altitude equations, the maximum range and altitude may be determined. Both equations for the range, equations 5 and 5a may be used to determine the maximum range by setting their derivatives to zero. For equation 5, range of the projectile is a function of $$v_h$$ and $$v_v$$ such that $$v_v^2+v_h^2=v^2$$ where v is the total initial velocity and is constant. Thus, the range may be expressed as a function of $$v_v$$ by solving for $$v_h$$:
 * $$v_h=\sqrt{v^2-v_v^2}$$ (Equation 8)

And substituting $$v_h$$ into equation 5:
 * $$d_h={ {2 v_h v_v} \over g } = { {2v_v \sqrt{v^2-v_v^2} } \over g} $$

The maximum $$d_h$$ may be determined by calculating the derivative and setting it to zero. The derivative is calculated as follows:
 * $$\frac{d}{dv_v} d_h={1 \over g} \frac{d}{dv_v} {2v_v \sqrt{v^2-v_v^2} } $$
 * $$={1 \over g} (2 \sqrt{v^2-{v_v}^2} +2v_v \frac{d}{dv_v} \sqrt{v^2-v_v^2} $$ (application of product rule)
 * $$={1 \over g} (2 \sqrt{v^2-{v_v}^2} +2v_v \frac{d \sqrt{v^2-v_v^2} }{d{v_v}^2} \frac{d{v_v}^2}{dv_v}) $$ (application of chain rule)
 * $$={1 \over g} (2 \sqrt{v^2-{v_v}^2} +2v_v (\frac{-1} {2 \sqrt{v^2-{v_v}^2}}) 2v_v) $$ (derivative of square root)
 * $$={1 \over g} (2 \sqrt{v^2-{v_v}^2} - \frac{2{v_v}^2}{\sqrt{v^2-{v_v}^2}}) $$ (simplify second term)

Set to zero and solve for $$v$$:
 * $$0={1 \over g} (2 \sqrt{v^2-{v_v}^2} - \frac{2{v_v}^2}{\sqrt{v^2-{v_v}^2}}) $$
 * $$\sqrt{v^2-{v_v}^2}=\frac {{v_v}^2}{\sqrt{v^2-{v_v}^2}}$$
 * $$v^2-{v_v}^2=v_v^2$$
 * $$v^2=2v_v^2$$ (Equation 9)

Thus maximum range occurs when $$v^2$$ is $$2v_v^2$$ and this can be substituted back into equation 8:
 * $$v_h=\sqrt{v^2-v_v^2}=\sqrt{v^2-v_v^2}=\sqrt{2v_v^2-v_v^2}=v_v$$

Thus the maximum range occurs when $$v_h=v_v$$.

The actual maximum range may now be calculated by substituting $$v_h=v_v$$ and equation 9 into equation 5:
 * $$d_h = { {2 v_h v_v} \over g } = { {2 v_v v_v} \over g } = { {2 v_v^2} \over g } = {v^2 \over g} $$

Maximum range in polar coordinates
The same conclusion may be drawn by starting with equation 5a.
 * $$\frac{d}{d\theta} d_h = \frac{d}{d\theta} {{ v^2 \sin 2 \theta } \over g} $$
 * $$= \frac{v^2}{g} \frac{d}{d2\theta} \sin 2 \theta \frac{d2\theta}{d\theta} $$ (application of chain rule)
 * $$= \frac{v^2}{g} (\cos 2 \theta) 2 \quad $$

Set to zero and solve for $$\theta$$:
 * $$0= \frac{v^2}{g} (\cos 2 \theta) 2 $$
 * $$0=\cos 2 \theta \quad $$

Now cosine is zero at $$\pi \over 2$$:
 * $$2 \theta=\frac \pi 2$$ (also directly clear from equation 5a, it gives the maximum possible sine value of 1)
 * $${\theta}_{\max} = \frac \pi 4 $$ radians

Thus the maximum range occurs when the angle is 45 degrees.

The actual maximum range may now be calculated by substituting 45 degrees into equation 5a:
 * $$d_h={{ v^2 \sin 2 \theta } \over g}={{v^2 \sin 2 ( \frac{\pi}{4} ) } \over g} = {v^2 \over g}$$

Maximum altitude at maximum range
Equations 6 and 6a may be used to calculate the maximum altitude at the maximum range. Equation 9 may be substituted into equation 6:
 * $$d_v=\frac{v_v^2}{2g}=\frac{(\frac{v^2}{2})}{2g}=\frac{v^2}{4g}$$

Likewise 45 degrees may be substituted into equation 6a:
 * $$d_v=\frac{v^2 {\sin}^2 \theta}{2g}=\frac{v^2(\frac{1}{\sqrt 2})^2}{2g}=\frac{v^2}{4g} $$

As a parabola
Equations 1 and 2 are parametric equations that describe a parabola. They may be rearranged into the more familiar quadratic form by solving equation 1 for $$t$$ and substituting into equation 2:

 * $$t=\frac{d_h}{v_h}$$ (rearrange equation 1 for $$t$$)

Substituting this into equation 2:
 * $$d_v=v_vt- \frac{gt^2}{2}=v_v(\frac{d_h}{v_h})-\frac{g(\frac{d_h}{v_h})^2}{2}=-\frac{g}{2{v_h}^2}(d_h)^2 + \frac{v_v}{v_h}(d_h)$$

This is now in the form
 * $$y=ax^2+bx+c \quad $$

where
 * $$y=d_v, x=d_h, a=-g/{2{v_h}^2}, b=v_v/v_h, c=0$$.

This is the form of a parabola and thus the trajectory is a parabola.

Likewise equations 1a and 2a can be rearranged into quadratic form. Equation 1a may be rearranged to:

 * $$t=\frac{d_h}{v \cos \theta}$$

And this may be substituted into equation 2a:

 * $$d_v=vt \sin \theta - \frac{gt^2}{2}=v \sin \theta \frac{d_h}{v \cos \theta} - \frac{g {(\frac{d_h}{v \cos \theta})}^2}{2} $$

Now $$\tan \theta=\sin \theta / \cos \theta$$, so:
 * $$d_v=-\frac{g}{2v^2{\cos}^2 \theta}d_h^2 + d_h \tan \theta $$ (Equation 10)

This is again now in the form $$y=ax^2+bx+c$$ where $$y=d_v\,$$, $$x=d_h\,$$, $$a=-g/{2v^2{\cos}^2 \theta}\,$$, $$b=\sin \theta / \cos \theta$$ and $$c=0\,$$ demonstrating that this is a parabola.

The quadratic formula gives the location of the intersection of the parabola and the x-axis. This is where the projectile trajectory starts and ends and thus may be used directly to calculate the range. In terms of rectilinear coordinate systems:

d_h=\frac{-b \pm \sqrt {b^2-4ac\ }}{2a}=\frac{-(v_v/v_h) \pm \sqrt{(v_v/v_h)^2 - 0} }{2(-g/2v_h^2)} = \frac{-v_v/v_h \pm v_v/v_h}{-g/v_h^2}=0, \frac{2{v_v}{v_h}}{g} \,$$

This is the same result as equation 5 above.

In polar coordinates and using the trigonometric identity $$ 2 \sin \theta \cos \theta = \sin 2 \theta\,$$, the intersections are:

d_h=\frac{-b \pm \sqrt {b^2-4ac\ }}{2a}=\frac{-(\sin \theta / \cos \theta) \pm \sqrt{(\sin \theta / \cos \theta)^2 - 0  }}{2(-g/2v^2 \cos^2 \theta)} =0, \frac{2 \sin \theta / \cos \theta}{g/v^2 \cos^2 \theta} = 0, \frac{2 v^2 \sin \theta \cos \theta}{g} = 0, \frac{v^2 \sin 2 \theta}{g} \,$$

This is the same result as in equation 5a above.

Similarly, the vertex of the parabola is the maximum altitude for a given range.

Computer simulation
NCLab provides an interactive graphical module for projective motion with and without air friction. The Python source code of the simulation can be freely view and copied. For the case with air friction, Runge-Kutta methods of orders 1, 2 and 4 are used to solve the underlying ordinary differential equations.

title: High School Physics/Projectile motion


text:
Talk:Blender 3D: Noob to Pro/Every Material Known to Man/Glass

I think should be a good idea explain something about lamps to achieve the desired effect.

Translucency 5?
The translucency slider only goes up to 1. And in the example panels at the foot of the page, the translucency is set to zero. 213.122.18.200 (talk) 12:14, 20 June 2010 (UTC)

glass not see thru in 3d view
Just in case anyone is stupid like me, this does not look transparent until you render. It is not transparent on the 3D view. Ickathu