text:
Talk:A-level Physics/Electrons, Waves and Photons/D.C. circuits

Specification
From the OCR GCE Physics A specification. Tick with ✔ when you feel each part of the specification has been covered. Try not to add much more than what is in this list as it would not appear in the exam anyway. Use links to wikipedia for more depth in a topic.

 * 1) Recall and use appropriate circuit symbols. ✔
 * 2) Draw and interpret appropriate circuit diagrams. ✔
 * 3) Use the concept that e.m.f. is defined in terms of the energy transferred by a source in driving unit charge round a complete circuit.
 * 4) Use energy considerations to distinguish between e.m.f. and p.d.
 * 5) Appreciate that sources of e.m.f. have internal resistance and understand the simple consequences of internal resistance for external circuits.
 * 6) Recall Kirchhoff’s first law and appreciate this as a consequence of conservation of charge.
 * 7) Understand Kirchhoff’s second law as a consequence of conservation of energy.
 * 8) Recall and use a formula for the combined resistance of two or more resistors is series.
 * 9) Recall and use a formula for the combined resistance of two or more resistors is parallel.
 * 10) Solve problems involving series and parallel circuits for one source of e.m.f.
 * 11) Understand the use of a potential divider as a source of variable p.d.
 * 12) Describe and explain the use of thermistors and light-dependant resistors in potential dividers to provide a potential difference which is dependant on temperature and on light intensity respectively.


text:
Talk:A-level Physics/Electrons, Waves and Photons/Electric current

Specification
From the OCR GCE Physics A specification. Tick with ✔ when you feel each part of the specification has been covered. Try not to add much more than what is in this list as it would not appear in the exam anyway. Use links to wikipedia for more depth in a topic.

 * 1) Understand electric current as a net flow of charged particles. ✔
 * 2) Understand the concept of charge in terms of the product of current and time. ✔
 * 3) Recall and use ∆Q=∆It. ✔
 * 4) Define the coulomb. ✔
 * 5) Appreciate the difference between the directions of conventional current and of electron flow. ✔
 * 6) Define potential difference and the volt in terms of energy transfer. ✔
 * 7) Recall and use V=W/Q and V=P/I ✔
 * 8) Sketch and explain the I/V characteristics of a metallic conductor at constant temperature, a semiconductor diode and a filament lamp. ✔
 * 9) Define resistance and the ohm. ✔
 * 10) Recall and use R=V/I ✔
 * 11) State Ohm’s law. ✔
 * 12) Define resistivity. ✔
 * 13) Recall and use ρ = RA/l ✔
 * 14) Recall and use P = I2R and P = V2/R ✔
 * 15) Recall and use W = IVt. ✔
 * 16) Sketch the variation with temperature of the resistance of a pure metallic conductor and of a negative temperature coefficient (NTC) thermistor.

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


text:
Wikijunior talk:Ancient Civilizations/Mound Builders

Controversial statement
I was thinking of adding this statement somewhere in this Wikijunior article, but I think the POV is way too strong not only for a Wikimedia project but even more so for Wikijunior:

"Unlike most other ancient civilizations and their modern counterparts, the modern country that inhabits the region that was anciently inhabited by this people does not wish to gain legitimacy by associating with the archeological findings of this civilization. Indeed, there seems to have been even from the beginning of the United States a systematic distruction of the mounds that were left behind, with mainly treasure hunters seeking to hang onto anything at all.  Even among native American Indian groups there doesn't seem to be a compelling interest in maintaining ties to this culture, and there have been several movements of people from outside this region even before European settlement of Anarctica."

I'd still like to add some sort of more NPOV statement that indicates that there is a significant difference in the objectives and goals of archeological research in North America compared to the rest of the world, primarily because the U.S. culture and government has basically no ties to this civilization except they happen to inhabit the same territory. Even so, this is a significant piece of the history of North America, that even many "native" people of North America know hardly anything about. Certainly this is something that American schools teach only in passing, even if the school itself is on the site of one of these former mounds. The prevelance of these mounds throughout North America can't be understated, and were found in place like even the residence of Thomas Jefferson, where at least he tried to do a more formal scientific archeological record of the items he found on his personal plantation, as well as sites in what is now Washington D.C. --Rob Horning 14:02, 5 September 2005 (UTC)

 * I'm not sure what "Unlike most other ancient civilizations and their modern counterparts, the modern country that inhabits the region that was anciently inhabited by this people does not wish to gain legitimacy by associating with the archeological findings of this civilization," or "Even among native American Indian groups there doesn't seem to be a compelling interest in maintaining ties to this culture, and there have been several movements of people from outside this region even before European settlement of North America." are supposed to mean exactly. --Shanel 04:24, 6 September 2005 (UTC)

 * I'm trying to refer to the fact that in most parts of the world, the "majority" of the people are largely related to the ancient inhabitants of the regions they live in. UK citizens have come from largely the British Isles and can in theory trace their ancestry to Roman times.  Same with most of Europe, Asia, and largely in Africa as well.  In the case of the Americas and Australia, however, aboriginal people tend to be a very small minority... for various reasons.  This is particularly so for the USA.  Archeological research takes on a very different tone than it does in Egypt, for example, where the Egyptian government genuinely tries to encourage research into the past and in many ways want to glorify the achievements of those ancient governments as much as its own.  This has been even more especially true with Iraq prior to the U.S. invasion, where Hussein made a very serious attempt to link his government to the ancient Babylonian government, considering himself in effect a modern version of the ancient Babylonian kings.  The Israeli government also does this, perhaps even more so, to show that they have a legitimate purpose to live in the land that they are on, and perhaps that they have a stronger claim on the land through archelogical evidence than the Palestianians (anciently called the Philistines....even called that now in Arabic).  That has a huge imact on any historical dig in that region of the world. I'm pointing out then that the U.S. government in many ways wants to diminish the historical impact of the Mound Builders for precisely the same reason:  the legitimacy of the U.S. government is called into question if you show that it is not the natural "heir" to an ancient civilization.  Instead, and as has been taught in many textbooks since the founding of the American republic, that the people who lived here in Southeastern Rhode Island were wild savages... perhaps noble and peaceful, but certainly in need of "settlement" and "education". In an attempt to try and keep this more with a NPOV theme, I'd like to try and lean more on educating perhaps some of the kids who live in North America to realize that the city they live in may in fact by considerably more ancient than the plaquards at the city gateway might state.  It is just that the names of the places have changed (not always) and a huge demographic change in the population has occured.  Many North American cities are also in the same place as many of the larger Mound Builder cities for many of the same reasons:  Access to waterways, natural resources that were close at hand, major trading route that converged at a certain point, and gaps in mountains.  I think knowing this is something that would amaze even most adults who live in North America, if they really stop and think about it.  And this was a major civilization by almost all criteria used to judge other similar groups of people.  Unfortunately, written records of these people is not easily obtained, and often heavily disputed when it does occur, together with considerable distruction of much of these sites in the 18th and 19th Centuries.  The 20th Century, however, usually brought considerably more preservation of these sites.  --Rob Horning 23:09, 7 September 2005 (UTC)

This is too complicated for the target audience. I don't think this is the right place for a full and balanced treatment of "How the West was Won/How the West was Lost", or for a thoughtful discussion of political motivations for historical research/archeological study. It is enough to say "Modern Egyptians are proud to say they are the descendants of the Ancient Egyptians". "Most people who live on or near ancient mounds don't even know they are there."

In order to show the contrast between how the civilizations are treated today, Change the grammatically incorrect "What country did they live in" to "Where did they live". Add, at the end, add "Who lives there Now".

Probably, we would say the moundbuilder civilization had less influence on the world than the major civilizations of Asia, Africa, and Europe. This would show in the list of "what is left to us" --SV Resolution 14:30, 8 September 2005 (UTC)

 * I think it is debatedable about who has had what kind of influence. Certainly the Iroquois Federation had a signifcant influence on the early founders of the American Republic.  Some would even go so far as to say that the early political leaders of America gathered many ideas from the very successful organization of the Iroquois to try and stitch together the original 13 colonies, and some aspects of the U.S. Constitution have surprisingly similar sections and clauses to the "constitution" of the Iroquois Federation.  And if that document hasn't had world-wide influence, I don't know what other document could have come close.  I've even heard it argued that had the English come to America just 100 years later, they probabally would have been pushed off of North America by the Iriquois. I know I'm just pushing something very etherial right here, and why I've even brought up the subject is that I want to include this civilization to be peers with the other civilizations.  --Rob Horning 23:28, 8 September 2005 (UTC)

Then that is something that can go into the "what is left to us section". Properly checked and attributed, of course. --SV Resolution 02:16, 9 September 2005 (UTC)


text:
Collection of Mathematical Formulas

 * About this book.
 * /References/.

Elementary Functions

 * /Inequalities/
 * /Trigonometry/
 * /Limits/
 * /Series/
 * Finite Series
 * Infinite Series

Special Functions

 * /Floor and Ceil/

Sequences

 * /Fibonacci Numbers/
 * /Harmonic Numbers/

title: Collection of Mathematical Formulas


text:
Talk:A-level Physics/Forces, Fields and Energy/Work and energy

Specification
From the OCR GCE Physics A specification. Tick with ✔ when you feel each part of the specification has been covered. Try not to add much more than what is in this list as it would not appear in the exam anyway. Use links to wikipedia for more depth in a topic.

 * 1) Give examples of energy in different forms, its conversion and conservation, and apply the principle of energy conservation to simple examples.
 * 2) Calculate the work done by a constant force in situations including those where the force is not in the same direction as the displacement.
 * 3) Recall and use the equation for kinetic energy, Ek = ½mv2
 * 4) Recall and use, the equation ∆Ep = mg∆h for potential energy changes near the Earth’s surface.


text:
Talk:A-level Physics/Forces, Fields and Energy/Motion in a circle

Specification
From the OCR GCE Physics A specification. Tick with ✔ when you feel each part of the specification has been covered. Try not to add much more than what is in this list as it would not appear in the exam anyway. Use links to wikipedia for more depth in a topic.

 * 1) Describe qualitatively motion in a curved path due to a perpendicular force, and understand the centripetal acceleration in the case of uniform motion in a circle.
 * 2) Express angular displacement in radians.
 * 3) Recall and use the centripetal acceleration a = v2/r
 * 4) Apply the equation F = ma to uniform motion in a circle to derive F = mv2/r

What needs to be done
I would really like it if somebody could donate a picture or two about the related stuff, and clean up the code a bit. I'm a newbie, so I'm having a lot of trouble at this. Also, some examples are needed. Thanks in advance to anyone willing to take it up.

 * Hi, and thanks for your contributions. The first place to check is Wikipedia. You can search for terms related to this module and use pictures from each article. For example, this article has a good picture showing what a radian is. You may also want to check through Wikimedia Commons for images and other media. Also, although I have only skimmed through your introduction, the entire A-level physics specification does not involve any differentiation. I will make a few changes to your text to make it fit the specification once I have looked at it thoroughly. Finally, please remember to check the specification to see what should and should not go on each page. --Krackpipe 12:07, 18 September 2005 (UTC)

 * Thanks a lot for the effort. I'm not sure exactly how to do a lot of this stuff without differentiation, because well, its the correct way. Either way, when I get some free time I'll get a way to put it into simpler terms. Thanks again for your corrections, which you made for my other page too.


text:
Talk:A-level Physics/Forces, Fields and Energy/Oscillations

Specification
From the OCR GCE Physics A specification. Tick with ✔ when you feel each part of the specification has been covered. Try not to add much more than what is in this list as it would not appear in the exam anyway. Use links to wikipedia for more depth in a topic.

 * 1) Understand and use the terms displacement, amplitude, period, frequency, and phase difference.
 * 2) Express period in terms of frequency.
 * 3) Define simple harmonic motion.
 * 4) Describe graphically the changes in displacement, velocity, and acceleration, during oscillations.
 * 5) Understand velocity as the gradient of the displacement-time graph.
 * 6) Recall and use a = -(2πf)2x, and the solutions x = Asin 2πft, x = Acos 2πft for simple harmonic motion.
 * 7) Describe practical examples of damped oscillations with particular reference to the effects of the degree of damping in such cases as a car suspension system.
 * 8) Describe practical examples of forced oscillations and resonance.
 * 9) Describe graphically how the amplitude of a forced oscillation changes with frequency near to the natural frequency of the system.


text:
Talk:A-level Physics/Forces, Fields and Energy/Gravitational fields

Specification
From the OCR GCE Physics A specification. Tick with ✔ when you feel each part of the specification has been covered. Try not to add much more than what is in this list as it would not appear in the exam anyway. Use links to wikipedia for more depth in a topic.

 * 1) understand a gravitational field as a field of force and define, recall and use gravitational field strength as force per unit mass. ✔
 * 2) Use field lines to represent a gravitational field. ✔
 * 3) Recall and use Newton’s law of gravitation for point masses in the form F = Gm1m2 / r 2. ✔
 * 4) Recall and use g = Gm / r 2 for the gravitational field strength of a point mass. ✔
 * 5) Appreciate that, on the surface of the Earth, the magnitude of g is approximately constant and equal to the acceleration of free fall. ✔

New inverse square law image
I have made a new diagram for the inverse square law which I think it much better. I will leave it up to the maintainers of this page to choose to use my new image: Image:Inverse_square_law.svg -- 82.153.70.188 (talk) 14:39, 2 April 2008 (UTC)

Radial fields
The first line of this topic reads: "The Earth has a radial field of gravity, which means that the gravitational field is circular and acts from the centre point." A circle is a 2 dimensional shape. Surely this should be "spherical"? EMT (Cardiff)


text:
Talk:A-level Physics/Forces, Fields and Energy/Electric fields

Specification
From the OCR GCE Physics A specification. Tick with ✔ when you feel each part of the specification has been covered. Try not to add much more than what is in this list as it would not appear in the exam anyway. Use links to wikipedia for more depth in a topic.

 * 1) Understand an electric field as an example of a field of force and define, recall and use electric field strength as force per unit positive charge. ✔
 * 2) Use field lines to represent an electric field. ✔
 * 3) Recall and use Coulomb’s law for point charges in a vacuum in the form F = kQ1Q2 / r 2, where k = 1 / 4πε0. ✔
 * 4) Recall and use E = kQ / r 2 for the electric field strength of a point charge. ✔
 * 5) Recall and use E = V/d for the magnitude of the uniform electric field strength between charged parallel plates. ✔
 * 6) Recognise the similarities of, and differences between, electric fields and gravitational fields. ✔

__________________________________________________________________________________________

I dunno how to discuss stuff in a wiki manner so ill just add it here. the bit about electric potential and the work required to move it seem to be described in the same way, give the same restult, yet the formula is different        W = k Q1Q2/r          &  V =k  Q/r  supposed to give the work required?? but one includes another charge

=Temporarily moved from the article page= I'm not sure how this exactly fits in, there's no explanation, and it doesn't directly follow on from the previous section (it was placed just before the "differences and similarities of fields". I'm leaving it here until I know what to do with it. Krackpipe (discuss • contribs) 11:07, 19 April 2011 (UTC)

Electric Potential and Work
Electric Potential is defined as the work that must be done to bring unit charge from infinity to a point in an electric field, a distance r from the center of the charge causing the field.

 * $${V}$$
 * $$= \frac {1} {4\pi\epsilon_0} \times \frac {Q} {r}$$
 * $$ = \frac {Q} {4\pi\epsilon_0 r}$$
 * }
 * $$ = \frac {Q} {4\pi\epsilon_0 r}$$
 * }

The electric field strength at the point where the unit charge is, is equal to the negative potential gradient at that point.

 * $${E}$$
 * $$=-\frac {dV} {dr}$$
 * $$= -\frac{d}{dr} \left( \frac {Q} {4\pi\epsilon_0 r} \right)$$
 * $$= -\frac {Q} {4\pi\epsilon_0} \times \frac{d}{dr} \left( \frac{1}{r} \right)$$
 * $$= \frac {Q} {4\pi\epsilon_0} \times \frac{1}{r^2}$$
 * $$= \frac {Q} {4\pi\epsilon_0 r^2}$$
 * }
 * $$= -\frac {Q} {4\pi\epsilon_0} \times \frac{d}{dr} \left( \frac{1}{r} \right)$$
 * $$= \frac {Q} {4\pi\epsilon_0} \times \frac{1}{r^2}$$
 * $$= \frac {Q} {4\pi\epsilon_0 r^2}$$
 * }
 * $$= \frac {Q} {4\pi\epsilon_0} \times \frac{1}{r^2}$$
 * $$= \frac {Q} {4\pi\epsilon_0 r^2}$$
 * }
 * $$= \frac {Q} {4\pi\epsilon_0 r^2}$$
 * }

Electric Potential Energy is defined as the work that must be done to bring a specific charge from infinity to a point in an electric field, a distance r from the centre of the charge causing the field.

 * $${U}$$
 * $$= \frac {1} {4\pi\epsilon_0} \times \frac {Q_1 Q_2} {r}$$
 * $$ = \frac {Q_1 Q_2} {4\pi\epsilon_0 r}$$
 * $$ ={Q_2 V}$$
 * }
 * $$ ={Q_2 V}$$
 * }
 * $$ ={Q_2 V}$$
 * }

The electric force acting on the charge is equal to the negative potential energy gradient at that point.

 * $${F}$$
 * $$=-\frac {dU} {dr}$$
 * $$= -\frac{d}{dr} \left( \frac {Q_1 Q_2} {4\pi\epsilon_0 r} \right)$$
 * $$= -\frac {Q_1 Q_2} {4\pi\epsilon_0} \times \frac{d}{dr} \left( \frac{1}{r} \right)$$
 * $$= \frac {Q_1 Q_2} {4\pi\epsilon_0} \times \frac{1}{r^2}$$
 * $$= \frac {Q_1 Q_2} {4\pi\epsilon_0 r^2}$$
 * }
 * $$= -\frac {Q_1 Q_2} {4\pi\epsilon_0} \times \frac{d}{dr} \left( \frac{1}{r} \right)$$
 * $$= \frac {Q_1 Q_2} {4\pi\epsilon_0} \times \frac{1}{r^2}$$
 * $$= \frac {Q_1 Q_2} {4\pi\epsilon_0 r^2}$$
 * }
 * $$= \frac {Q_1 Q_2} {4\pi\epsilon_0} \times \frac{1}{r^2}$$
 * $$= \frac {Q_1 Q_2} {4\pi\epsilon_0 r^2}$$
 * }
 * $$= \frac {Q_1 Q_2} {4\pi\epsilon_0 r^2}$$
 * }

Electric potential energy and electric potential
120.60.16.100 (discuss) 09:34, 22 August 2012 (UTC)No information on both of them120.60.16.100 (discuss) 09:34, 22 August 2012 (UTC)


text:
Talk:A-level Physics/Forces, Fields and Energy/Capacitors

Specification
From the OCR GCE Physics A specification. Tick with ✔ when you feel each part of the specification has been covered. Try not to add much more than what is in this list as it would not appear in the exam anyway. Use links to wikipedia for more depth in a topic.

 * 1) ✔ Define capacitance and the farad.
 * 2) ✔ Recall and use C = Q / V.
 * 3) ✔ Use formulae for the capacitance of capacitors in series and in parallel.
 * 4) Recall and use W = ½QV, for the energy of a charged capacitor.
 * 5) Describe the discharge of a capacitor through a resistor, sketch graphs showing the variation with time of the potential difference, charge stored and current during this discharge.
 * 6) Appreciate the practical importance of time constant for discharge of a capacitor through a resistor.
 * 7) Recall τ = CR for the time constant of a capacitor-resistor circuit.
 * 8) Use equations of the form x = x0 e-t/CR for the discharge of a capacitor.


text:
Talk:A-level Physics/Forces, Fields and Energy/Electromagnetism

Specification
From the OCR GCE Physics A specification. Tick with ✔ when you feel each part of the specification has been covered. Try not to add much more than what is in this list as it would not appear in the exam anyway. Use links to wikipedia for more depth in a topic.

 * 1) Recall and use F = BIlsinθ, with directions as interpreted by Fleming’s left-hand rule, for the force on a current-carrying conductor in a uniform magnetic field.
 * 2) Recall and use F = BQv, for the force on a charge moving in a uniform magnetic field.
 * 3) Analyse the circular orbits of charged particles moving in a plane perpendicular to a uniform magnetic field by relating the electromagnetic force to the centripetal acceleration it causes.


text:
Talk:A-level Physics/Forces, Fields and Energy/Electromagnetic induction

Specification
From the OCR GCE Physics A specification. Tick with ✔ when you feel each part of the specification has been covered. Try not to add much more than what is in this list as it would not appear in the exam anyway. Use links to wikipedia for more depth in a topic.

 * 1) Define magnetic flux and the Weber.
 * 2) Recall and use Φ = BA.
 * 3) Define magnetic flux linkage, NΦ.
 * 4) Recall and use Faraday’s law of electromagnetic induction.
 * 5) Recall and use Lenz’s law to determine the direction of an induced e.m.f.
 * 6) Recall and use the equation magnitude of induced e.m.f. = rate of change of flux linkage.


text:
Talk:A-level Physics/Forces, Fields and Energy/Thermal physics

There's things on latent heat that are supposed to be in the specification, and they're definately in the exam. I must have gotten an outdated specification.--Krackpipe 14:35, 19 January 2006 (UTC)

I've also just crossed out one point that doesnt seem to be in the current spec. --Krackpipe 17:36, 19 January 2006 (UTC)

So there was a question in last Janurary's paper that asked about a suitable method to determine the specific heat capacity of an aluminium block. Decided to add that back in. ---Krackpipe 19:42, 13 June 2006 (UTC)

May be we can add a couple of examples in the page, for instance, conversion between temperature scales, mixing problems, idea gas equation problems, etc. ---Kiwakwok (discuss • contribs) 04:24, 18 June 2014 (UTC)

Specification
From the OCR GCE Physics A specification. Tick with ✔ when you feel each part of the specification has been covered. Try not to add much more than what is in this list as it would not appear in the exam anyway. Use links to wikipedia for more depth in a topic.

 * 1) Show an awareness that internal energy is determined by the state of the system and can be expressed as the sum of a random distribution of kinetic and potential energies associated with the molecules of the system.  ✔
 * 2) Relate a rise in temperature of a body to an increase in internal energy.  ✔
 * 3) Demonstrate knowledge that there is an absolute scale of temperature which does not depend upon the physical property of any particular substance, i.e. the thermodynamic scale.  ✔
 * 4) Appreciate that, on the thermodynamic (Kelvin) scale, absolute zero is the temperature at which all substances have a minimum internal energy.  ✔
 * 5) Show familiarity with temperatures measured in kelvin and degrees Celsius.   ✔
 * 6) Define and use specific heat capacity, and show an awareness of the principle of its determination by an electrical method. ✔
 * 7) Recall and use ∆Q = mc∆θ. ✔
 * 8) Describe melting and boiling in terms of energy input without a change in temperature. ✔
 * 9) Recall and use the ideal gas equation pV = nRT, where n is the amount of gas in moles.
 * 10) Appreciate that one mole is 6.02 x 1023 particles and that 6.02 x 1023 mole-1  is the Avogadro constant NA.
 * 11) Recall that the mean kinetic energy of a molecule of an ideal gas is proportional to the thermodynamic temperature.


text:
Talk:A-level Physics/Forces, Fields and Energy/The nuclear atom

Specification
From the OCR GCE Physics A specification. Tick with ✔ when you feel each part of the specification has been covered. Try not to add much more than what is in this list as it would not appear in the exam anyway. Use links to wikipedia for more depth in a topic.

 * 1) Demonstrate a qualitative understanding of the α-particle scattering experiment and the evidence this provides for the existence, charge and small size of the nucleus. ✔
 * 2) Demonstrate a qualitative understanding of X-ray diffraction and the evidence this provides for crystal structure. ✔
 * 3) Demonstrate a qualitative understanding of neutron diffraction and the evidence this provides for crystal structure. ✔
 * 4) Demonstrate a qualitative understanding of electron diffraction and the evidence this provides for the spacing of atoms. ✔
 * 5) Demonstrate a qualitative understanding of high-energy electron scattering and the evidence this provides for the radius of the nucleus.  ✔
 * 6) Show an awareness of the relative sizes of nuclei, atoms and molecules.
 * 7) Distinguish between nucleon (mass) number and proton (atomic) number. ✔
 * 8) Understand that an element can exist in various isotopic forms, each with a different number of neutrons.
 * 9) Use the usual notation for the representation of nuclides and represent simple nuclear reactions by nuclear equations.
 * 10) Appreciate the equivalence between mass and energy, and recall and use the equation ∆E = ∆mc2.
 * 11) Appreciate that nuclear processes involve the conservation of charge and of mass-energy.
 * 12) Describe the processes of nuclear fission and nuclear fusion and appreciate that these reactions involve a release of energy.


text:
Talk:A-level Physics/Forces, Fields and Energy/Radioactivity

Specification
From the OCR GCE Physics A specification. Tick with ✔ when you feel each part of the specification has been covered. Try not to add much more than what is in this list as it would not appear in the exam anyway. Use links to wikipedia for more depth in a topic.

 * 1) appreciate the spontaneous and random nature of radioactive decay of unstable nuclei. ✔
 * 2) describe the nature, penetration and range of α-particles, β-particles and γ-rays as different types of ionising radiation. ✔
 * 3) represent radioactive decay by nuclear equations. ✔
 * 4) show an awareness of the hazards of ionising radiation and the safety precautions which should be taken in the handling, storage and disposal of radioactive materials. ✔
 * 5) define the terms activity and decay constant. ✔
 * 6) recall and use A = λN. ✔
 * 7) recognise, use and represent graphically solutions of the decay law bases on x = x0e -λt for activity, number of undecayed nuclei and corrected count rate. ✔
 * 8) define half-life as the mean time for the number of nuclei of a nuclide to halve. ✔
 * 9) use the relation λt½ = 0.693. ✔

spontaneity of a radioactive nucleus implies that it is not affected by environmental conditions such as temperature or pressure.


text:
Ada Programming/Libraries/Ada.Numerics.Generic Elementary Functions

is a unit of the Predefined Language Environment since Ada 95.

The generic package defines various mathematical functions for floating point type. Being generic it can not only be used for predefined floating point types but also for any user defined floating type.

Usage
There is an extensive usage guide in Ada Programming/Mathematical calculations. Here the relevant extract:

; Numeric_4 Value_Type  12 -999_999_999_999.0e999 .. 999_999_999_999.0e999; Value_Functions  Ada.Numerics.Generic_Elementary_Functions (      Value_Type);

Specification
Float_Type Pure Generic_Elementary_Functions Sqrt X           Float_Type  Float_Type Log X           Float_Type  Float_Type Log X Base     Float_Type  Float_Type Exp X           Float_Type  Float_Type ""   Left Right  Float_Type  Float_Type Sin X           Float_Type  Float_Type Sin X Cycle    Float_Type  Float_Type Cos X           Float_Type  Float_Type Cos X Cycle    Float_Type  Float_Type Tan X           Float_Type  Float_Type Tan X Cycle    Float_Type  Float_Type Cot X           Float_Type  Float_Type Cot X Cycle    Float_Type  Float_Type Arcsin X           Float_Type  Float_Type Arcsin X Cycle    Float_Type  Float_Type Arccos X           Float_Type  Float_Type Arccos X Cycle    Float_Type  Float_Type Arctan Y            Float_Type X           Float_Type  10 Float_Type Arctan Y            Float_Type X           Float_Type  10 Cycle       Float_Type  Float_Type Arccot X            Float_Type Y           Float_Type  10 Float_Type Arccot X            Float_Type Y           Float_Type  10 Cycle       Float_Type  Float_Type Sinh X           Float_Type  Float_Type Cosh X           Float_Type  Float_Type Tanh X           Float_Type  Float_Type Coth X           Float_Type  Float_Type Arcsinh X           Float_Type  Float_Type Arccosh X           Float_Type  Float_Type Arctanh X           Float_Type  Float_Type Arccoth X           Float_Type  Float_Type AdaNumericsGeneric_Elementary_Functions

Wikibook

 * Ada Programming
 * Ada Programming/Libraries/Ada


text:
Talk:Physics Study Guide/Gravity

hello palse. I need information about acceleration due to gravity

title: Talk:Physics Study Guide/Gravity


text:
Talk:Consciousness Studies/Nineteenth To Twenty First Century Philosophy

Phenomenal consciousness
When I started adding information about "phenomenal" consciousness to Consciousness studies (24 August 2005) the section on The neuroscience of consciousness uncritically (without discussion on that page and without reference to discussion elsewhere) introduced the dualistic distinction between "phenomenal" and "access" consciousness. It was suggested that neuroscience currently investigates "access" consciousness but "phenomenal" consciousness eludes scientific explanation.

 * Thank you for adding a link, there is a lack of links in the book. RobinH 20:14, 5 September 2005 (UTC).

I searched the Consciousness studies wikibook for discussion of the distinction between "phenomenal" and "access" consciousness. I found discussion of these categories of consciousness at the page on "The conflict", so I made a link from the word "phenomenal" in The neuroscience of consciousness to The conflict. In The conflict, I started adding information about Block's division of consciousness into "phenomenal" and "access" consciousness.

The information about Block was then moved to the page about Nineteenth and twentieth century philosophy. I continued to edit that page, providing both a description of Block's ideas and a description of why neuroscientists resist Block's division of consciousness into "phenomenal" and "access" consciousness.

 * Your discussion was about Block rather than the whole issue raised on the page: Phenomenal consciousness and access consciousness and is an interesting addition to twentieth century philosophers.

On 5 September 2005 User:RobinH removed from Nineteenth and twentieth century philosophy the account of why neuroscientists resist Block's division of consciousness into "phenomenal" and "access" consciousness.

This comment was inserted: "why is this relevant to Block? It is discussed in great depth later" in place of the account of why neuroscientists resist Block's division of consciousness into "phenomenal" and "access" consciousness. The edit (03:07, 5 September 2005 RobinH) was described as:

(NPOV remove subjective text (what computer scientists feel) ! Remove rant against skepticism)

The entire account of Block's division of consciousness into "phenomenal" and "access" consciousness was added to Consciousness studies in an attempt to counter an uncritical account of this dualistic division and its relevance to neuroscience. Neuroscientists do not accept Block's dualism and it is important to say so.

 * The division into phenomenal and access consciousness is not dualism. Phenomenal consciousness could be a non-algorithmic physical phenomenon such as proposed by Pribram and Bohm or Penrose and Hammeroff or Green or Stapp etc. However, given that Turing machines are algorithmic it would suggest that phenomenal consciousness is not something that is done by digital computers. RobinH

To remove the account of why neuroscientists do not accept Block's dualism while asking, "why is this relevant to Block?" misses the whole point of why the account was added.

 * Many neuroscientists accept the concept of phenomenal consciousness, certainly cognitivists and most indirect realist neurophysiologists would be in this category. I know many neurophysiologists and would say that indirect realism is the conventional wisdom in that field. RobinH

Block's dualistic account of consciousness is depicted in Consciousness studies as being of fundamental importance to the neuroscience of consciousness, a view that is rejected by most neuroscientists. It is entirely relevant to add discussion of this issue. If the objection by User:RobinH is simply that the reaction of neuroscientists to Block should not be a part of the Block section of Nineteenth and twentieth century philosophy, then it should be moved to another page. The material about Block was originally being added to another page that deals with the dualistic distinction between "phenomenal" and "access" consciousness. User:RobinH is the editor who moved the account of Block's dualistic distinction between "phenomenal" and "access" consciousness (and reaction to it) to "Nineteenth and twentieth century philosophy".

User:RobinH seems to be justifying removal of the account of the views of neuroscientists because such accounts do not present a neutral point of view. However, the original depiction by Consciousness studies of the fundamental importance of the dualistic distinction between "phenomenal" and "access" consciousness to the neuroscience of consciousness was not itself a neutral point of view. The material about how neuroscientists react to Block's dualistic distinction between "phenomenal" and "access" consciousness was added to Consciousness studies as an attempt to counter the original bias of the book.

According to the introduction:

"Everyone has their own view of the nature of consciousness based on their education and background, the intention of this book is to expand this view by providing an insight into the various ideas and beliefs on the subject as well as a review of current work in neuroscience. The neuroscientist should find the philosophical discussion interesting because this provides first person insights into the nature of consciousness and also provides some subtle arguments about why consciousness is not a simple problem."

If a goal of this book is "providing an insight into the various ideas and beliefs on the subject" then it seems strange to delete descriptions of why some neuroscientists, computer scientists and some philosophers question the "first person insights into the nature of consciousness" that have been proclaimed by philosophers such as Block. --JWSurf 16:42, 5 September 2005 (UTC)

Response by RobinH 19:43, 5 September 2005 (UTC)
Firstly please forgive me for editing so aggressively. My problem with the pieces that were deleted is described below.

The first piece that was taken out is the following:

 * Many neurobiologists and computer scientists feel that philosophers such as Block and Searle are overly-pessimistic about the power of "computation", "program" or "algorithm" to produce human-like consciousness. The study of "computation", "program", "algorithm" and consciousness is too primitive for us to be able to trust our intuitions about exactly what is possible for computational algorithms to accomplish. Further, it may not matter what we call physical processes that can generate consciousness as long as we can figure out what they are and how to work with them. Thus, neurobiologists and computer scientists feel justified in continuing to search for the physical basis of consciousness and for ways to endow man-made devices with human-like consciousness. Further, despite warnings from philosophers, neurobiologists and computer scientists often suspect that conventional physical accounts of brain processes and some form of computational algorithm can be found to explain consciousness and allow us to instantiate it in robots.

My gripe with this is it is about what the author believes to be the prevailing opinion amongst neuroscientists. If Searle is overly pessimistic then the author should quote who has analysed Searle and found him to be wrong and why. Searle's argument is basically the same as Leibniz's concern, a computer can be made out of mechanical parts but would a set of rolling steel balls have your experience at any instant? Can the author find a paper that argues convincingly that a set of steel balls could be conscious? The gripe is about a personal opinion that is unsupported by references to how Searle is wrong.

There is always a tendency in this debate to confuse Searle's attack on information processing in digital computers with the wider physicalist versus dualist debate. Digital computers are not the only route to artificial consciousness and Searle is attacking digital computers (Turing type information processors). I believe that artificial consciousness must be possible in some way but not using Turing machines (after all, we are conscious).

The second bit that I cut was:

 * Some philosophers such as Thomas Nagel have claimed a fundamental distinction between the first person experience of consciousness and any third person account of the mechanisms by which consciousness is generated. If philosophers can be overly-pessimistic about what neuroscientists and computer scientists can accomplish from the third person perspective, they might also be overly-enthusiastic about the reliability of first person introspection. Some philosophers have been fundamentally skeptical about our ability to be certain about anything we observe from the first person perspective. Despite any sense we me have about our inability to be be wrong about our subjective evaluations of our own consciousness, it may be wise to keep an open mind and remain open to the possibility that phenomenal consciousness is not a distinct category from access consciousness. For example, they may be at the two ends of a continuous spectrum of consciousness for which some forms of consciousness are easier to imagine as being algorithmically generated than others.

I had a problem with this because Nagel is pointing out that there is a thing, personal phenomenal experience. You are saying that you have an explanation for that thing - digital computing (algorithmic generation). However, there is no reference to how Nagel's thing is explained by digital computing/algorithms or even how we might set about explaining it in terms of digital computing/algorithms. Wittgenstein is really attacking the cogito. You might have invoked Dennett who does the same in the context of computers. Dennett gives up trying to explain personal experience in terms of digital computing and also attacks incorrigibility and suggests that personal experience does not exist as a thing at all. In other words, according to Dennett, the only way that we can say that people are digital computers/algorithms is to deny the very thing that we want to explain - phenomenal experience. But is Dennett or Wittgenstein relevant to the excised paragraph? The paragraph says that digital computers/algorithms will explain phenomenal consciousness, it does not say that, like Dennett (an extremist Eliminativist philosopher), we can just ignore the whole problem by redefining experience in functionalist terms. But doubting incorrigibility does make the phenomenon go away, there is still something to be explained and we are still lacking a digital/algorithmic explanation. The gripe is that you are using veiled references to attacks on incorrigibility in support of the idea that digital computers/algorithms could be conscious. The thesis needs references to papers that show how digital computers/algorithms could, in principle, be phenomenally conscious or needs to develop the idea that phenomenal consciousness does not exist (see below).

Dennett was vague in his "Consciousness Explained" about all this. He invokes eliminativism then, later in the book, claims that phenomenal consciousness will emerge from complexity. He cannot have it both ways! If consciousness emerges then how does a digital computer do that? On the other hand, if Dennett really believes that phenomenal consciousness does not exist he should stick to that (but then he would be a zombie).

These were the principle changes that I made. The other changes were to add references to work by physicists who believe that there may be non-digital computing forms of artificial consciousness and to point out that the idea that human beings are digital computers or simple information processors is highly contentious. Most of the neuroscientists I have known and know do not believe that we are simply information processors - most would either look to some sort of emergentism or unexplained physics (which is almost the same thing) or just say that they don't know how consciousness is done!

Lastly I pointed out that Block is just the last in a long line of people who have drawn to our attention the cognitivist vs behaviourist divide. Even Aristotle mentions it! Is it a biased basis for this book to simply accept the divide and run with it?

See: The problem of machine and digital consciousness where the problem of artificial consciousness is discussed and where it is noted that you can be a physicalist (non-dualist) without accepting that we are Turing Machines.

One last word, welcome aboard JWSchmidt, this is going to be a rocky ride of a book.

Thanks for the welcome
"If Searle is overly pessimistic then the author should quote who has analysed Searle and found him to be wrong and why."

I'm not sure that many neurobiologists would label as "wrong" Searle's position as given here. However, Searle has contributed to the perception of neurobiologists that many philosophers are too centered on their inability to imagine how physical brain processes can account for consciousness. Gerald Edelman expressed this sentiment in "Naturalizing consciousness: A theoretical framework" (Proc Natl Acad Sci U S A. 2003 April 29; 100(9): 5520–5524; see the last sentence and Edelman's reference 25).

 * Edelman is almost at the same place as Block philosophically he says: "Primary consciousness is the state of being mentally aware of things in the world--of having mental images in the present" and "In contrast, higher-order consciousness involves the recognition by a thinking subject of his or her own acts or affections". Primary consciousness, mental images at the present instant, is phenomenal consciousness and higher-order consciousness is access consciousness. It is complex, but definitely feasible to provide an algorithmic explanation of higher order consciousness but primary consciousness is far more difficult - how can we be mentally aware of images at the present instant? As neuroscientists such as Penfield and Newman & Baars and philosophers from time immemorial have pointed out primary/phenomenal consciousness is a 'state'. This was why I chose Green's article as the definition of the problem of consciousness, Green defines phenomenal consciousness in physical terms see: http://en.wikibooks.org/wiki/Consciousness_studies:_The_description_of_consciousness

RobinH 09:05, 6 September 2005 (UTC)

Philosophers seem very concerned with the mystery of consciousness and neuroscientists like Edelman and Koch just want to get on with their research. Edelman started his article by warning against dualism, and it is Block's dualistic distinction between the natures of A and P consciousness that provokes distrust and leads to the inability of scientists to adopt Block's distinction between A and P consciousness.

What we are dealing with here is differences in the intuitions of philosophers and neuroscientists (and AI researchers, too) about the nature of consciousness and our ability to use the tools of science to make sense of consciousness and possibly attain the technical capacity to produce consciousness in man-made devices. I find it strange that there could be honest doubt about the existence of differences in these intuitions between people working in different fields such as neuroscience, philosophy of mind, and computer science. In my view, we have a case of the blind men and the elephant. Each specialized discipline has its own perspective on consciousness. Different people take "program" to mean different things. We are bewitched by the language we use. I hope a way can be found to clearly make this point in Consciousness studies. I hope that the wiki environment can help lead to better communication between specialized disciplines and a more coordinated attack on consciousness and eventual understanding. --JWSurf 04:45, 6 September 2005 (UTC)

Husserl and bracketing
Concerning: "the intention to move, the movement and the sensation of movement are bound or 'bracketed' together into a single meaning."

Bracketing has more to do with the Husserlian epoche than with semantics or psychological intention. As I understand bracketing, it is what we do when we postpone our judgement in the epoche. For instance, when considering an experience, in order to reach its pureness we must bracket the ego.Ex.

hello there. i'm sure this is a bad way to do research but i wondered if 'other minds' is a problem with naturalism, if that's what the qualia arguments boil down to? is there anything i could be reading i'm taking a module in sciientific realism in Januray? thanks :o


text:
Do-It-Yourself

Welcome to the Wikibooks Do-It-Yourself Kit (DIY). Contained here are some of the coolest projects you'll ever find, from how to make your own biodiesel to canning your own food, to building a railgun!

Introduction and Preparation

 * /Introduction/ - Why build things yourself?
 * /Basic tools/ - Tools you'll need for many of these projects
 * /Safety/ - General safety measures
 * /Difficulty and practicality/ - Which projects can I do myself?
 * /Common procedures/

Consumables

 * Biofuels:
 * /Vegoil/
 * /Bioethanol/
 * /Biobutanol/
 * /Biodiesel/
 * /Reusable menstrual pads/
 * /Soap/ and /Shampoo/
 * /Shoe polish/
 * /Wine/

Weaponry

 * /Gauss gun/
 * /Railgun/
 * /Sword/

Fixing Things

 * /Fixing a dishwasher/
 * /Unclogging drains/

Polishing and Improving

 * /Clean jewelry/
 * /Faux marbling/
 * /Field stripping m16/
 * /Home staging/
 * /Polishing silver/
 * /Household seismic safety/
 * /Wooden reed care/

Miscellaneous/Uncategorized

 * /Bodkin point/
 * /Business card box/
 * /Campfire/
 * /Drone/
 * /Homemade hydroponics wick system/
 * /House insulation/ - Installing insulation in your house or other building
 * Levitation and antigravity
 * /Ionic wind thruster/
 * /Pottery/
 * /Tablet stand/
 * /Upgrading your car audio/
 * /Wooden boat/
 * /Breed siamese fighting fish/
 * /Canning/
 * /Satellite dish installation/ How to install a satellite dish, including free-to-air digital satellite
 * /Printing onto calico fabric using an inkjet printer/

title: Do-It-Yourself


text:
A-level Mathematics/OCR/C3/Differentiation

Currently, the only functions that you are able to differentiate are relatively simple ones. We will now have a look at some more complicated functions and some new techniques to differentiate them.

Derivatives of the Natural Functions
The natural functions have two special derivative that you need to memorize. The derivative $$\operatorname{e}^{x}$$ is unique because its derivative is itself. If there is a constant in the index then the derivative will be multiplied by the constant. The derivative of $$\ln x\,$$ is important because any constant in front of x will be dropped in the derivative.

 * $$\frac{d}{dx} \operatorname{e}^{kx} = k\operatorname{e}^{kx}$$
 * $$\frac{d}{dx}\ln x = \frac{1}{x}$$
 * The derivative of an exponential function to any base is: $$\frac{d}{dx}\operatorname{a}^x=\operatorname{a}^x\ln(\operatorname{a})$$

Example
Find the derivative of $$y = \operatorname{e}^{6x} + \ln 5x$$.

Using the rules we get:

$$\frac{dy}{dx} = 6\operatorname{e}^{6x} + \frac{1}{x}$$

Remember: $$\ln 5x = \ln 5 + \ln x \,$$, so $$\frac{d}{dx}\ln 5x = \frac{d}{dx}\ln 5 + \ln x = 0 + \frac{1}{x}$$.

The Product Rule
The Product Rule states if $$y = f\left(x\right)\cdot g\left(x\right)\,$$ then $$\frac{dy}{dx}=f'\left(x\right)g\left(x\right)+f\left(x\right)g'\left(x\right)$$.

Example
Find the derivative of $$y = x^2\cdot 18x$$

$$\frac{dy}{dx}=2x\cdot18x+x^2\cdot18$$

$$\frac{dy}{dx}=36x^2+18x^2$$

$$\frac{dy}{dx}=54x^2$$

The Quotient Rule
The Quotient Rule states: If $$ y = \frac{f(x)}{g(x)}$$ then $$ \frac{dy}{dx} = \frac{f^'(x)g(x) -g^'(x)f(x)}{\left\{g(x)\right\}^2} $$.

Example
Find the derivative of $$y = \frac{5x + 3}{2x - 1}$$.

$$\frac{dy}{dx} = \frac{5\times\left(2x - 1\right) - \left(5x + 3\right)\times2}{\left\{2x - 1\right\}^2}$$

$$\frac{dy}{dx} = \frac{10x -5 -10x - 6}{\left\{2x - 1\right\}^2}$$

$$\frac{dy}{dx} = \frac{-11}{\left\{2x - 1\right\}^2}$$

The Chain Rule
The Chain Rule states: If $$ y = f[g(x)]\,$$ then $$ \frac{dy}{dx} = f^'[g(x)]\cdot g^'(x)$$.

Example
Find the derivative of $$y = \left(2x^2 - 3\right)^2$$

$$\frac{dy}{dx} = 2\left(2x^2 - 3\right)4x$$

$$\frac{dy}{dx} = 8x\left(2x^2 - 3\right)$$

The Derivative of the Inverse Function
If we want the derivative of the inverse function we need to use the following rule: $$ \frac{dy}{dx} = \frac{1}{\frac{dx}{dy}}\ if\ \frac{dx}{dy} \ne 0$$.

Example
What is the derivative of the inverse of $$f\left(x\right) = \frac{x - 1}{x + 2}$$ ?

Find the derivative of the original function using the quotient rule.

$$\frac{dy}{dx} = \frac{3}{(x+2)^2}$$

To find the derivative of the inverse we use the rule.

$$\frac{dx}{dy} = \frac{(x+2)^2}{3}$$

Connected Rates of Change
Differentiation can be used for situations where you need to find the maximum or minimum value of a problem depending on variables that affect each other. Problems involving connected rates of changes are very diverse and are used in a lot of practical applications such as find the maximum volume of a box from the least amount of cardboard to calculating how long it will take a container to become filled. You will need to write out the problems algebraically and then use the first derivatives to find the maximum or minimum values. The general steps are:

 * 1) The first step is listing what we know and what shape we are dealing with.
 * 2) The second second step is to figure what we need to solve for.
 * 3) If the quantities are related solve for one variable in terms of the other.
 * 4) The third step is the set up the equation and differentiate with respect to the variable.
 * 5) Then input all the relevant knows into the equation.
 * 6) If any data is missing see if you can obtain it from an equation.
 * 7) Finish the problem.
 * 8) Write the answer.

Example 1: Sliding Ladder
If a moving ladder (C) 6 metres long is leaning against a wall and the distance between the wall and the bottom of the ladder increases at a rate of 1.5 metres per second how fast is the top of the ladder moving down the wall when the bottom of the ladder is 3 metres from the wall?

 * 1) The first step is listing what we know and what shape we are dealing with.
 * 2) The shape is a triangle. So we will be using $$a^2 + b^2 = c^2$$.
 * 3) A = ? B = 3 $$\frac{db}{dt} = 1.5$$ C = 6
 * 4) The second step is to figure what we need to solve for.
 * 5) $$\frac{da}{dt}$$
 * 6) The third step is the set up the equation and differentiate with respect to the variable. Which is time in this equation.

 * 1) $$2a\frac{da}{dt} + 2b\frac{db}{dt} = 0\frac{dc}{dt}$$
 * 2) Then input all the relevant knows into the equation.
 * 3) $$a\frac{da}{dt} + 3\times1.5 = 0$$
 * 4) If any data is missing see if you can obtain it from an equation.
 * 5) $$a^2 + 3^2 = 6^2$$
 * 6) $$a = 3\sqrt{3}$$
 * 7) Finish the problem.
 * 8) $$3\sqrt{3}\frac{da}{dt} + 3\times1.5 = 0$$
 * 9) $$\frac{da}{dt} = - \frac{4.5}{3\sqrt{3}}$$
 * 10) When the bottom of the ladder is 3 metres away from the wall the top will be sliding down at a rate of $$- \frac{4.5}{3\sqrt{3}} \frac{metres}{s} = \frac{\sqrt{3}}{2}\frac{metres}{s}$$.

Example 2: Filling of a Conical Shape
If sand is being poured on the ground in a conical shape at a rate of 5 cubic centimetres a minute. The sand is piling up such that the radius of the pile is equal to the height of the pile. How fast is the radius growing when the sand pile has a volume of 9π cubic centimetres?
 * 1) The first step is listing what we know and what shape we are dealing with.
 * 2) The Shape is a cone. The Formula for the volume of a cone is $$v = \frac{1}{3}\pi r^2h$$.
 * 3) V = 9π, $$\frac{dv}{dt}=5$$, r = h
 * 4) The second step is to figure what we need to solve for.
 * 5) $$\frac{dr}{dt}$$
 * 6) The third step is to set up the equation and differentiate with respect to time.
 * 7) $$v = \frac{1}{3}\pi r^2h$$
 * 8) Since r = h we have $$v = \frac{1}{3}\pi r^3$$
 * 9) $$\frac{dv}{dt} = \pi r^2 \frac{dr}{dt}$$
 * 10) Then input all the relevant knowns into the equation.
 * 11) $$5 = \pi r^2 \frac{dr}{dt}$$
 * 12) If any data is missing see if you can obtain it from an equation.
 * 13) $$9\pi = \frac{1}{3}\pi r^3$$
 * 14) $$r = 3$$
 * 15) Finish the problem.
 * 16) $$5 = \pi 3^2 \frac{dr}{dt}$$
 * 17) $$\frac{dr}{dt} = \frac{5}{9\pi}$$
 * 18) When the volume is 9π $$cm^3$$ the radius will be growing at a rate of $$\frac{5}{9\pi} \frac{cm}{min}$$.

Example 3: Maximum Area
Given a rope of 5 meters, what is the biggest area that it can engulf if it is shaped into a rectangle?

What have we got?

Finding an expression for $$y$$:

Finding an expression for the area that only depends on $$x$$:

Now, let $$f(x)$$ be the function for the area of the rectangle:

$$f(x)=\frac{5}{2}*x-x^2$$

Find the derivative, $$f'(x)$$:

$$f'(x) = \frac{5}{2} - 2x$$

Finding $$y$$ when $$x$$ is $$\frac{5}{4}$$

$$2*\frac{5}{4} + 2y = 5$$

$$2y = 5 - \frac{5}{2}$$

$$2y = \frac{5}{2}$$

$$y = \frac{5}{2}*\frac{1}{2}$$

$$y=\frac{5}{4}$$

So, the optimal size of the rectangle is $$\frac{25}{16} m^2$$, with the length of all sides at $$\frac{5}{4} m$$.


text:
Ada Programming/Libraries/Ada.Numerics.Generic Complex Types

is a unit of the Predefined Language Environment since Ada 95.

The generic package defines complex type for a defined floating point type. Being generic it can not only be used for predefined floating point types but also for any user defined floating type.

Usage
There is an extensive usage guide in Ada Programming/Mathematical calculations. Here the relevant extract:

Ada.Numerics.Generic_Complex_Types; Numeric_7 Value_Type  12 -999_999_999_999.0e999 .. 999_999_999_999.0e999; Complex_Types  Ada.Numerics.Generic_Complex_Types (      Value_Type); Complex_Types.Complex;

Specification
Real Pure Generic_Complex_Types Complex Re Im Real Imaginary Preelaborable_Initialization Imaginary i  Imaginary j  Imaginary Re X Complex    Real Im X Complex    Real Im X Imaginary  Real Set_Re X    Complex Re      Real Set_Im X    Complex Im      Real Set_Im X      Imaginary Im      Real Compose_From_Cartesian Re Im Real  Complex Compose_From_Cartesian Re     Real  Complex Compose_From_Cartesian Im     Imaginary  Complex Modulus X     Complex  Real ""  Right  Complex  Real  Modulus Argument X     Complex    Real Argument X     Complex Cycle Real  Real Compose_From_Polar Modulus Argument        Real Complex Compose_From_Polar Modulus Argument Cycle Real Complex ""      Right  Complex  Complex ""      Right  Complex  Complex Conjugate X     Complex  Complex "" Left Right Complex  Complex "" Left Right Complex  Complex "" Left Right Complex  Complex "" Left Right Complex  Complex "" Left Complex Right  Integer  Complex ""      Right  Imaginary  Imaginary ""      Right  Imaginary  Imaginary Conjugate X     Imaginary  Imaginary  "-" ""    Right  Imaginary  Real "" Left Right Imaginary  Imaginary "" Left Right Imaginary  Imaginary "" Left Right Imaginary  Real "" Left Right Imaginary  Real "" Left Imaginary Right  Integer  Complex "" Left Right  Imaginary  Boolean "" Left Right Imaginary  Boolean "" Left Right  Imaginary  Boolean "" Left Right Imaginary  Boolean "" Left Complex   Right  Real  Complex "" Left Real Right  Complex    Complex "" Left Complex   Right  Real  Complex "" Left Real Right  Complex    Complex "" Left Complex   Right  Real  Complex "" Left Real Right  Complex    Complex "" Left Complex   Right  Real  Complex "" Left Real Right  Complex    Complex "" Left Complex   Right  Imaginary  Complex "" Left Imaginary Right  Complex    Complex "" Left Complex   Right  Imaginary  Complex "" Left Imaginary Right  Complex    Complex "" Left Complex   Right  Imaginary  Complex "" Left Imaginary Right  Complex    Complex "" Left Complex   Right  Imaginary  Complex "" Left Imaginary Right  Complex    Complex "" Left Imaginary Right  Real  Complex "" Left Real Right  Imaginary  Complex "" Left Imaginary Right  Real  Complex "" Left Real Right  Imaginary  Complex "" Left Imaginary Right  Real  Imaginary "" Left Real Right  Imaginary  Imaginary "" Left Imaginary Right  Real  Imaginary "" Left Real Right  Imaginary  Imaginary Imaginary  Real i  Imaginary  10 j  Imaginary  10 AdaNumericsGeneric_Complex_Types

Wikibook

 * Ada Programming
 * Ada Programming/Libraries
 * Ada Programming/Mathematical calculations


text:
Rueda de Casino/Pelota

Enchufa then before changing to the next partner, the leader stamps his right foot twice (beats 1 and 3), then claps twice (beats 5 and 7). The follower stamps her left twice and claps twice at the same time as the leader. Followed by a Dile Que No.

This can be called as Pelota Con Cuatro, which is the same but with 4 stamps and 4 claps. Alternatively, Pelota con Dos signals the four stamps "with two (claps)" (i.e., clap on each of the last two stamps).

The name might refer to the noisy skittering of the ball around the roulette wheel.

title: Rueda de Casino/Pelota


text:
SPM/Haemodynamic Response Function

Generally speaking, cognitive processing is associated with increases in neuronal firing rates. The increased neural activity leads to increased metabolic requirements for the neurons. The onset of neural activity leads to a systematic series of physiological changes in the local network of blood vessels that include changes in the cerebral blood volume per unit of brain tissue (CBV), changes in the rate of cerebral blood flow (CBF), and changes in the concentration of oxyhaemoglobin and deoxyhaemoglobin.

There are different fMRI techniques that can pick up a functional signal corresponding to changes in each of the previously mentioned components of the haemodynamic response. The most common functional imaging signal is the Blood Oxygenation Level Dependent signal (BOLD), which primarily corresponds to the concentration of deoxyhaemoglobin. In simple terms, the magnetic resonance signal comes from exciting hydrogen nuclei with a radiofrequency pulse, and detecting the radio waves emitted as the nuclei return to a lower-energy configuration. Deoxyhaemoglobin has different magnetic properties than oxyhaemoglobin - it is paramagnetic, which means that it will make the local magnetic field over a microscopic domain inhomogeneous. This has the effect of dephasing the signal emitted by the nuclei in this domain, causing destructive interference in the observed MR signal. Over a macroscopic domain (i.e., one functional voxel) greater amounts of deoxyhaemoglobin lead to less signal. The functional BOLD signal is seen as an increase in the MR signal that corresponds to a decrease in the concentration of deoxyhaemoglobin. The decrease of deoxy-Hb concentration is seen because the increase in CBF following neural activity more than accounts for the effect of increased uptake of oxygen.

For the purposes of estimating the BOLD signal in an experimental paradigm, SPM makes use of a canonical haemodynamic response function (HRF). This function is assumed to be the response of the system (as reflected by the MR signal) to a brief, intense period of neural stimulation. The SPM HRF is shown in the graph on the right, and exhibits a rise peaking at 5 sec, followed by an undershoot that persists for a considerable period (with a peak around 15 sec). The code for this graph is below.

>> RT = 0.5; hrf = spm_hrf(RT); plot(0:RT:32, hrf);

In this graph, the y-axis is in arbitrary units. A common way to plot the impulse response is in units of percent signal change from a baseline condition. A very robust stimulus (such as a contrast taken between a flickering visual stimulus and no visual stimulus) may produce changes on the order of 2%-4% in the BOLD signal. The change observed in contrasts involving higher-level cognitive processes is typically much smaller.

title: SPM/Haemodynamic Response Function


text:
ACT Study Guide/QOTD

This page is meant for the question of the day. Hopefully we will have a question of the day or a question of the week that is written by a contributor to Wikibooks. If it changes to a question of the week, the address will change to http://en.wikibooks.org/wiki/ACT/QOTW. Until then, you can follow this link to the Number 2 ACT Question of the Day.

title: ACT Study Guide/QOTD


text:
Movie Making Manual/North Carolina

The best "one stop" location for information on the Film Industry in North Carolina can be found at Charlotte Regional Partners - Film Production Office.

Another website to research is the Charlotte Film and Video Association.

The State of NC has been host to several block busters including "The Patriot", "Gettysburg", and many more. Visit the sites for more details.

Central Piedmont Community College is now offering certificate courses in Film and Video Production. []

/Local resources

title: Movie Making Manual/North Carolina


text:
Talk:Technical Analysis

Before moving contents to section I am going to dump some more content on the first page. Once I get some clear sectioning I will move contents to their respective sections.(Yndesai (talk))

Over and above giving brief about basic of technical analysis and asking the reader to look for more information on various reference, I want to make this wikibook more about how an individual can use technical analysis in small simple steps, I may create a section of wikibook in this direction if required. (Yndesai (talk) 05:51, 23 December 2010 (UTC))

There is lot to technical analysis then what is written. Psychology is NOT the basis of the technical analysis. The Psychology as explained is more about the economics and the creation and burst of bubble this is not due to technical analysis. The basis technical analysis is the study of the forces of demand and supply of stock. Technical analysis discount any of the fundamental or news related justifications and just view any of the stock price movement as the result of the demand and supply.

It is said that the price is the ultimate truth and it includes all the elements into it.

Also there are lot of indicators which are statistical tools used for technical analysis which needs mention.

I would like to elaborate this section in this direction any comments.

Case Study
One of the case that comes to my mind is the Satyam stock listed on NSE / BSE in India Which had a major fraud by its CEO and the stock fell like a hell.

(Yndesai (talk) 05:04, 17 December 2010 (UTC))

This page of course needs a lot of work, but that's OK, I'm glad I found it.

I re-wrote the almost unitelligible section entitled TRADING TECHNIQUES as follows:

""Trading" can be characterized as short-term decisons made in accordance with information gleaned from technical analysis. Traders usually move in and out of the market at a rapid pace in hopes of repeatedly extracting small profits. Trading is helpful in that it serves the useful purpose of enhancing liquidity.  Full time traders often use multiple computer screens   to monitor prices closely throughout the trading day. For people who cannot spend all day in front of a computer monitor, one option is to anticipate substantial price moves so that the associated risk of taking a position is justified by the upside profit potential. "( Source: Pattern Recogniation and Trading decisions, SatchWell,Chris 2005)"

Hope this helps.

Ps This is the first article I've worked on that doesn't have a liberal bias. I guess there's still hope in the world! 68.40.151.220 23:36, 5 September 2005 (UTC)

A suggested URL - http://chart.nu
I actually am quite enamored of your opening statement/paragraph. Technical analysis has been the basis for real-time trading decision for my evolution from investor (years holding period) down to scalper (hours per trade). It has been mostly a matter of being able to recognize patterns as they evolve over time and speeding up the process into tighter timeframes and quicker decisions. Coming from a software development background, it was fairly straightforward to take my understanding of pattern trading and put it into a chart format. The result of that effort can be found at http://chart.nu/ along with explanations of how technical analysis combined with an understanding of individual risk profile can lead to winning strategies.

Perhaps you would consider including a link to my website for further reading? In general, it is a goal to keep the site commercial/ad - free since it is a working tool bench for my daily scanning and trading decision process. Although there is sparse in-depth content, I hope to add to library in the future, mostly on subjects of risk profiles, pattern evolution, and stock filtering. If you would like, I can also contribute to this wiki (note: an editorial first for me.)

Thanks for your consideration,

voodoo

Work needed
This article desperately needs work, you can't just leave quotes under sub-titles in an attempt to explain concepts!!

It needs explanation rather than unsourced quotes

title: Talk:Technical Analysis


text:
Software Engineers Handbook/Language Dictionary/Visual J++

Visual J++
Here is the Java wikipedia entry.

Type
Visual J++ is a full, procedural, object-oriented, visual language.

Execution Entry Point
public static void main(String args[]) {    // some functionality here }

General Syntax
The typical statement is completed by a semi-colon. For the assignment of b to a use: a = b;

Comments
// this is an inline comment. Everything after the // is a comment. Block comments are specified by a starting /* and ending */ They can span multiple lines. /* * this is a block comment */

Variable Declarations
int x = 9; Integer y = new Integer(4);

Method Declaration/Implementation
// declaration private return_type class_name::function_name(argument_1_type arg_1_name,                           argument_2_type arg_2_name,                            default_argument_type default_arg_name) { // implementation // work with arg_1_name, arg_2_name, and default_arg_name // depending on the argument types the variables are passed by     //   value, reference, or are constant // don't forget to return something of the return type return 36; }

Scope
Scope is defined by curly braces. { // this the beginning of a scope // the scope is about to end }

Conditional Statements
If and only if A is equal to B assign C to D, otherwise, assign E to F. if( A == B ) {    D = C;     // more code can be added here. It is used if and only if A is equal to B } else {    F = E;     // more code can be added here. It is used if and only if A is not equal to B } or if( A == B ) D = C; //more lines of code are not permitted after this statement else F = E;

Alternatively, a switch statement can be used for multiple choice operations. This sample converts a number input to text. switch( number_value ) {    case 37: text = "thirty-seven"; break; // this line prevents the program from writing over this value with the //  following code case 23: text = "twenty-three"; break; default: // this is used if none of the previous cases contain the value text = "unknown number"; }

Looping Statements
This code counts from 0 to 9, adding up the contents of the array. int i = 0; for( int index = 0; index < 10; index = index + 1 ) {    i = array[index]; }

This code repeats until the number 4 is found. If this runs off of the end of the array, there could be a problem. int index = 0; while( 4 != array[index] ) {    index = index + 1; }

This code increments the counter before the check is made, so that it starts with element 1. int index = 0; do { index = index + 1; } while( 4 != array[index] );

Output Statements
System.out.println( "Hello World!" ); And adding text to visual components.

Containers
Containers inherit from the Collection class. See the java.util package for specific containers including Vector.

Algorithms
''What algorithms does it have? Does sort work in J++?''

Garbage collection
Garbage collection is automatic.

Physical Structure
Code is generally kept in files with a .java extension. It is compiled into Java byte code into files with .class extensions.

Tips
= // assignment == // comparison, is equal to Often using the one you don't want will compile, and will produce results you did not expect.
 * The language is very similar to Java.
 * Visual form layout and component access is similar to other Microsoft Visual development languages.
 * Classes in the Java packages are capitalized, methods are not.
 * Everything is a pointer. Use a clone method to avoid operating on the original element of a Collection.
 * Arrays start with index 0.
 * Don't confuse these two:

Web References

 * Java wikibooks page
 * Microsoft support is available at the [Microsoft Developers Network] pages.

Books and Articles
paper references here


text:
User:Jbland

Hello, my name is Joe Land The following text is a test. I don't fully understand how to use this Wiki-thing. So, I am going to practice on this page. How exciting!

$$y = x^2 + 2$$

What a complicated equation...

title: User:Jbland


text:
Engineering Acoustics/Characterizing Damped Mechanical Systems

Characterizing Damped Mechanical Systems
Characterizing the response of Damped Mechanical Oscillating system can be easily quantified using two parameters. The system parameters are the resonance frequency ($$w resonance$$ and the damping of the system $$Q  (quality factor)or B  (Temporal Absorption)$$. In practice, finding these parameters would allow for quantification of unknown systems and allow you to derive other parameters within the system.

Using the mechanical impedance in the following equation, notice that the imaginary part will equal zero at resonance.

($$Z_m = F/u = R_m + j(w*M_m - s/w)$$)

Resonance case:($$w*M_m = s/w$$)

Calculating the Mechanical Resistance
The decay time of the system is related to 1 / B where B is the Temporal Absorption. B is related to the mechancial resistance and to the mass of the system by the following equation.

$$B = Rm / 2*Mm$$

The mechanical resistance can be derived from the equation by knowing the mass and the temporal absorption.

Critical Damping
The system is said to be critically damped when:

$$Rc = 2*M*sqrt(s/Mm) = 2*sqrt(s*Mm) = 2*Mm*wn$$

A critically damped system is one in which an entire cycle is never completed. The absorption coefficient in this type of system equals the natural frequency. The system will begin to oscillate, however the amplitude will decay exponentially to zero within the first oscillation.

Damping Ratio
$$Damping Ratio = Rm/Rc$$

The damping ratio is a comparison of the mechanical resistance of a system to the resistance value required for critical damping. Rc is the value of Rm for which the absorption coefficient equals the natural frequency (critical damping). A damping ratio equal to 1 therefore is critically damped, because the mechanical resistance value Rm is equal to the value required for critical damping Rc. A damping ratio greater than 1 will be overdamped, and a ratio less than 1 will be underdamped.

Quality Factor
The Quality Factor (Q) is way to quickly characterize the shape of the peak in the response. It gives a quantitative representation of power dissipation in an oscillation.

$$Q = wresonance / (wu - wl)$$

Wu and Wl are called the half power points. When looking at the response of a system, the two places on either side of the peak where the point equals half the power of the peak power defines Wu and Wl. The distance in between the two is called the half-power bandwidth. So, the resonant frequency divided by the half-power bandwidth gives you the quality factor. Mathematically, it takes Q/pi oscillations for the vibration to decay to a factor of 1/e of its original amplitude.

Back to Main page


text:
User:Mshonle/Policy

Immediate Exclusions
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title: User:Mshonle/Policy


text:
Cryptography/Index of coincidence

The index of coincidence for a ciphertext is the probability that two letters selected from it are identical. Usually denoted by I, it is a statistical measure of the redundancy of text. The index of coincidence of totally random collection (uniform distribution) of letters is around 0.0385.

title: Cryptography/Index of coincidence