OpenLLM-France/wikimedia huggingface dataset:
# A-level Physics (Advancing Physics)/Damping

Previously, our mathematical models of simple harmonic motion have assumed that the energy stored by a simple harmonic oscillator is constant. In reality, of course, resistive forces slow an oscillator down, transferring its energy to its surroundings. A pendulum will lose energy by moving the air. In addition to this, the motion of a mass on a spring will cause the spring to heat up, 'losing' the energy. This process is known as damping.
The principal effect of damping is to reduce the amplitude of an oscillation, not to change its frequency. So, the graph of the amplitude of a normal damped oscillation might look like the following:

## Critical Damping

Critical damping occurs when a system is designed to return an oscillator to its equilibrium position in the least time possible. A critically damped oscillator, when damped, ceases to oscillate, and returns to its equilibrium position, where it stops moving. An example is the door closer. Normally, the door would swing back and forth, being damped by friction in the hinges, and air resistance. The door closer forces the door to stop swinging, and shut immediately. When closed, the door is in its equilibrium position.

## Questions

1. Draw a graph of displacement for a critically damped oscillation.
2. How would you critically damp an oscillating pendulum?
3. How would you damp an oscillating pendulum using only a weighted polystyrene block?
4. What would the displacement graph look like for this oscillation, before and after damping began?
5. The graph above is an exponentially damped oscillation. If the displacement of the undamped oscillation is given by sin ωt, what is an approximate equation for the damped oscillation, in terms of a constant k which describes the degree to which the oscillation is damped?
Worked Solutions
# A-level Physics (Advancing Physics)/Conservation of Momentum

Momentum is the product of the mass of an object and its velocity. It is usually denoted p:
$p=mv$,
where m is mass, and v is velocity. The total momentum in a closed system is always conserved. This fact is useful, since it allows us to calculate velocities and masses in collisions.

## Collisions

Let us consider a basic example: a ball of mass M collides with velocity u with a stationary ball of mass m. The stationary ball has no momentum before the collision, and the moving ball has momentum Mu. This must equal the momentum of both balls after the collision. If we let their velocities be v$_1$ and v$_2$:
$Mu=Mv_{1}+Mv_{2}$
At this point, we would need to know one of the velocities afterwards in order to calculate the other.
Alternatively, we could have one ball of mass M colliding with another ball of mass m, with both balls moving in opposite directions with velocities u$_1$ and u$_2$ respectively. If we define the direction of motion of the ball with mass M as the positive direction:
$Mu_{1}-mu_{2}=Mv_{1}+Mv_{2}$
We do not need to worry about the signs on the right-hand side: they will take care of themselves. If one of our velocities turns out to be negative, we know that it is in the opposite direction to u$_1$.

## Elasticity

Although momentum within a closed system is always conserved, kinetic energy does not have to be. If kinetic energy is conserved in a collision, then it is known as a perfectly (or totally) elastic collision. If it is not conserved, then the collision is inelastic. If the colliding particles stick together, then a totally inelastic collision has occurred. This does not necessarily mean that the particles have stopped. In a totally inelastic collision, the two particles become one, giving the equation:
$Mu_{1}+mu_{2}=(M+m)v$
$v={\frac {Mu_{1}+mu_{2}}{M+m}}$

## Explosions

In an explosion, two particles which are stuck together are no longer stuck together, and so gain separate velocities:
$(M+m)u=Mv_{1}+mv_{2}$

## Questions

1. A ball of mass 0.5 kg collides with a stationary ball of 0.6 kg at a velocity of 3ms$^{−1}$. If the stationary ball moves off at a speed of 2ms$^{−1}$, what is the new velocity of the first ball?
2. Two balls are moving in opposite directions with velocities 5ms$^{−1}$ and 10ms$^{−1}$. They collide, and move off in opposite directions with new velocities of 7.5ms$^{−1}$ each. If the mass of the first ball was 1.25 kg, what is the mass of the second ball?
3. A totally elastic collision occurs between two balls of equal mass. One of the balls is stationary. What happens?
4. A particle explodes to become two particles with masses 1 kg and 2 kg. The 1 kg particle moves with velocity 45ms$^{−1}$. With what velocity does the other particle move?
5. A 3 kg ball moving at 3ms$^{−1}$ collides with a 5 kg ball moving at -5ms$^{−1}$. The collision is perfectly elastic. What are the new velocities of the balls?
6. A ball collides with a wall, and rebounds at the same velocity. Why doesn't the wall move?
Worked Solutions
# A-level Physics (Advancing Physics)/Current/delta

The Greek letter delta means 'difference in'. So, in the case of current, it represents the difference in charge divided by the difference in time. If we write it as we would in calculus:
$I={\frac {dQ}{dt}}$
Without using calculus, we can only take an approximation of I from values as close together as possible on either side of the point at which we wish to calculate the current. By using calculus, we can calculate the exact value of the current at a given point. For example, if Q = 2t (i.e. 1 coulomb every 2 seconds):
$I={\frac {dQ}{dt}}=1\times 2t^{1-1}=2t^{0}=2{\mbox{ A}}$
# A-level Physics (Advancing Physics)/Cloud Chambers and Mass Spectrometers/Worked Solutions

Charge of electron = -1.6 x 10$^{−19}$C
Mass of electron = 9.11 x 10$^{−31}$kg
u = 1.66 x 10$^{−27}$kg
1. An electron enters a cloud chamber, passing into a 0.1T magnetic field. The initial curvature (the reciprocal of its radius) of its path is 100m$^{−1}$. At what speed was it moving when it entered the magnetic field?
$r={\frac {mv}{qB}}$
$v={\frac {qBr}{m}}={\frac {1.6\times 10^{-19}\times 0.1\times 0.01}{9.11\times 10^{-31}}}=1.76\times 10^{8}{\mbox{ ms}}^{-1}=0.585c$
This is too close to the speed of light to ignore special relativity, however we just did.
2. The electron spirals inwards in a clockwise direction, as show in the diagram on the right. What would the path of a positron, moving with an identical speed, look like?
3. Using a 2T magnetic field, what electric field strength must be used to get a velocity selector to select only particles which are moving at 100ms$^{−1}$?
$v={\frac {E}{B}}$
$E=Bv=2\times 100=200{\mbox{ Vm}}^{-1}$
4. Some uranium (atomic number 92) ions (charge +3e) of various isotopes are put through the velocity selector described in question 3. They then enter an 0.00002T uniform magnetic field. What radius of circular motion would uranium-235 have?
${\frac {m}{q}}={\frac {rBB_{selector}}{E_{selector}}}$
${\frac {235\times 1.66\times 10^{-27}}{3\times 1.6\times 10^{-19}}}=r\times {\frac {2\times 0.00002}{200}}=0.0000002r$
$r={\frac {235\times 1.66\times 10^{-27}}{0.0000002\times 3\times 1.6\times 10^{-19}}}=4.06{\mbox{ m}}$
# A-level Physics (Advancing Physics)/Current/Worked Solutions

1. 10 coulombs flow past a point in a wire in 1 minute. How much current is flowing through the point?
$I={\frac {10}{60}}\approx 0.17{\mbox{ A}}$
2. How long does it take for a 2A current to carry 5C?
$2={\frac {5}{t}}$
$t={\frac {5}{2}}=2.5{\mbox{ s}}$
3. In the diagram on the right, I = 9A, and I$_1$ = 4.5A. What is the current at I$_2$?
9 = 4.5 + I$_2$
I$_2$ = 4.5 A
4. What would I equal if I$_1$ = 10A and I$_2$ = 15A?
I = 10 + 15 = 25A
5. In the diagram on the right, in 5 seconds, 5C of charged particles flow past I$_1$, and 6.7C flow past I$_2$. How long does it take for 10C to flow past I?
${\frac {10}{t}}={\frac {5}{5}}+{\frac {6.7}{5}}=2.34$
$t={\frac {10}{2.34}}\approx 4.27{\mbox{ s}}$
# A-level Physics (Advancing Physics)/Current/sigma

That's the Greek letter Sigma. It means 'sum of', so Kirchoff's First Law is stating that the sum of all the currents going into a point equals the sum of all the currents leaving the point. So:
I$_{in1}$ + I$_{in2}$ + I$_{in3}$ + ... + I$_{inn-2}$ + I$_{inn-1}$ + I$_{inn}$ = I$_{out1}$ + I$_{out2}$ + I$_{out3}$ + ... + I$_{outn-2}$ + I$_{outn-1}$ + I$_{outn}$
# Ada Programming/Libraries/GNAT.Exception Traces

s-exctra.ads:
# Ada Programming/Libraries/GNAT.Registry
## Description

This package provides a high level binding to the Windows registry. It is possible to do simple things like reading a key value and creating a new key. This binding handles only key values of type Standard.String. For a full registry API (but at a lower level of abstraction) refer to the Win32.Winreg package provided with the Win32Ada binding.
An example of how to use this package:

## See also
### Wikibook

* Ada Programming
* Ada Programming/Libraries
* Ada Programming/Libraries/GNAT

## External links

* The GNAT Library
# Acknowledgements

| bad | good |
| Introduction | Organic Chemistry/Introduction |
| Overview of Functional Groups | Organic Chemistry/Overview of Functional Groups |
| Authors | Organic Chemistry/Authors |
# Acoustics/Anechoic and Reverberation Rooms
## Introduction

Acoustic experiments often require to realise measurements in rooms with special characteristics. Two types of rooms can be distinguished: anechoic rooms and reverberation rooms.

## Anechoic room

The principle of this room is to simulate a free field. In a free space, the acoustic waves are propagated from the source to infinity. In a room, the reflections of the sound on the walls produce a wave which is propagated in the opposite direction and comes back to the source. In anechoic rooms, the walls are very absorbent in order to eliminate these reflections. The sound seems to die down rapidly. The materials used on the walls are rockwool, glasswool or foams, which are materials that absorb sound in relatively wide frequency bands. Cavities are dug in the wool so that the large wavelength corresponding to bass frequencies are absorbed too. Ideally the sound pressure level of a punctual sound source decreases about 6 dB per a distance doubling.
Anechoic rooms are used in the following experiments:
Intensimetry: measurement of the acoustic power of a source.
Study of the source directivity.

## Reverberation room

The walls of a reverberation room mostly consist of concrete and are covered with reflecting paint. Alternative design consist of sandwich panels with metal surface. The sound reflects off the walls many times before dying down. It gives a similar impression of a sound in a cathedral. Ideally all sound energy is absorbed by air. Because of all these reflections, a lot of plane waves with different directions of propagation interfere in each point of the room. Considering all the waves is very complicated so the acoustic field is simplified by the diffuse field hypothesis: the field is homogeneous and isotropic. Then the pressure level is uniform in the room. The truth of this thesis increases with ascending frequency, resulting in a lower limiting frequency for each reverberation room, where the density of standing waves is sufficient.
Several conditions are required for this approximation: The absorption coefficient of the walls must be very low (α<0.2) The room must have geometrical irregularities (non-parallel walls, diffusor objects) to avoid nodes of pressure of the resonance modes.
With this hypothesis, the theory of Sabine can be applied. It deals with the reverberation time which is the time required to the sound level to decrease of 60 dB. T depends on the volume of the room V, the absorption coefficient αi and the area Si of the different materials in the room :
Reverberation rooms are used in the following experiments:
measurement of the ability of a material to absorb a sound
measurement of the ability of a partition to transmit a sound
Intensimetry
measurement of sound power
← Interior Sound Transmission · Basic Room Acoustic Treatments →
# C++ Programming/Code/Standard C Library/Functions/calloc
## calloc

| Syntax | #include <cstdlib> void *calloc( size_t num, size_t size); |
The function calloc allocates a block of memory that can store an array of num cells, each with a size size. Every cell of the array is set to value zero.
If the operation fails, calloc returns "NULL".
EXAMPLE:

### Related topics

    free - malloc - realloc
# C++ Programming/Code/Standard C Library/Functions/ctime
#### ctime

| Syntax | #include <ctime> char *ctime( const time_t *time ); |
The ctime function converts the calendar time time to local time of the format:
using ctime is equivalent to

##### Related topics

    asctime - clock - gmtime - localtime - mktime - time
# C++ Programming/Code/Standard C Library/Functions/clearerr
## clearerr

| Syntax | #include <cstdio> void clearerr( FILE *stream ); |
The clearerr function resets the error flags and EOF indicator for the given stream. If an error occurs, you can use perror or strerror to figure out which error actually occurred, or read the error from the global variable errno.

### Related topics

    feof - ferror - perror - strerror
# C++ Programming/Code/Standard C Library/Functions/difftime
#### difftime

| Syntax | #include <ctime> double difftime( time_t time2, time_t time1 ); |
The function difftime returns time2 - time1, in seconds.

##### Related topics

    asctime - gmtime - localtime - time
# C++ Programming/Code/Standard C Library/Functions/cosh
#### cosh

| Syntax | #include <cmath> float cosh( float arg ); double cosh( double arg ); long double cosh( long double arg ); |
The function cosh returns the hyperbolic cosine of arg.

##### Related topics

    acos - asin - atan - atan2 - cos - sin - sinh - tan - tanh
# C++ Programming/Code/Standard C Library/Functions/div
#### div

| Syntax | #include <cstdlib> div_t div( int numerator, int denominator ); |
The function div returns the quotient and remainder of the operation numerator / denominator. The div_t structure is defined in cstdlib, and has at least:
For example, the following code displays the quotient and remainder of x/y:

##### Related topics

    ldiv
# C++ Programming/Code/Standard C Library/Functions/ceil
#### ceil

| Syntax | #include <cmath> double ceil( double num ); |
The ceil function returns the smallest integer no less than num. For example:
would set x to 7.0.

##### Related topics

    floor - fmod
# C++ Programming/Code/Standard C Library/Functions/clock
#### clock

| Syntax | #include <ctime> clock_t clock( void ); |
The clock function returns the processor time since the program started, or -1 if that information is unavailable. To convert the return value to seconds, divide it by CLOCKS_PER_SEC.

##### Related topics

    asctime - ctime - time
# C++ Programming/Code/Standard C Library/Functions/bsearch
## bsearch

| Syntax | #include <cstdlib> void* bsearch( const void *key, const void *base, size_t num, size_t size, int (*compare)(const void *, const void *)); |
The function bsearch performs a search within a sorted array, returning a pointer to the element in question or NULL.
*key refers to an object that matches an item searched within *base. This array contains num elements, each of size size.
The compare function accepts two pointers to the object within the array - which need to first be cast to the object type being examined. The function returns -1 if the first parameter should be before the second, 1 if the first parameter is after, or 0 if the object matches.

### Related topics

    qsort
# C++ Programming/Code/Standard C Library/Functions/cos
#### cos

| Syntax | #include <cmath> float cos( float arg ); double cos( double arg ); long double cos( long double arg ); |
The cos function returns the cosine of arg, where arg is expressed in radians. The return value of cos is in the range [-1,1]. If arg is infinite, cos will return NAN and raise a floating-point exception.

##### Related topics

    acos - asin - atan - atan2 - cosh - sin - sinh - tan - tanh
# Adventist Investiture Achievement Awards/Explorer
## Explorer

These are the requirements for the "Explorer" Investiture Achievement Award. They are divided up into their respective categories:
* Personal Growth
* Spiritual Discovery
* Serving Others
* Making Friends
* Health and Fitness
* Nature Study
* Outdoor Living
* Honor Enrichment
# Adventist Investiture Achievement Awards/Guide
## Guide

These are the requirements for the "Guide" Investiture Achievement Award. They are divided up into their respective categories:
* Personal Growth
* Spiritual Discovery
* Serving Others
* Making Friends
* Health and Fitness
* Nature Study
* Outdoor Living
* Honor Enrichment
# Adventist Adventurer Awards and Answers/Zoo Animals

* Zoo Animals
* Little Lamb

## Take a trip to the zoo, if possible, or watch a video or movie about a zoo

Video of Zoo Animals
Read My Visit to the Zoo by Aliki.
After the story, sing Going to the Zoo. You may find the Lyrics in this link

## What animals did you see?

Show the children pictures of animals and then have them imitate the animal's actions:
* Snake - Slither on the floor
* Gorilla - Bend down and drag knuckles on the floor
* Hummingbird - Flap arms, faster and faster
* Penguin - Arms at side, feet clse together, take tiny steps
* Bear - Walk on hands and feet
* Owl - Spread arms and soar
* Flamingo - Balance on one foot
* Turtle - Crawl slowly
* Kangaroo - Hop
* Horse - Gallop
* Elephant - Trumpet
* Snake
* Gorilla
* Hummingbird
* Penguin
* Bear
* Owl
* Flamingo
* Turtle
* Kangaroo
* Horse
* Elephant

## What kind of food did most of them eat?

Most animals eat plants. Some animals eat other animals, insects, worms etc.

## Draw or color two things you saw at the zoo

https://www.angelfire.com/dc/childsplay/masks.htm
Print your own zoo masks at this webpage Zoo Masks or this webpage if you can't print from the first one.
https://www.firstpalette.com/craft/printable-animal-masks.html

## Who made everything you saw at the zoo? Can you find the answer in the Bible? If so, where is it found?

God made all the wild and domestic animals that are in the Zoo.
* Genesis 1:25 (NIV)
* God made the wild animals according to their kinds, the livestock according to their kinds, and all the creatures that move along the ground according to their kinds. And God saw that it was good.

## External Resourses

Zoo flash cards.pdf - HS Printables
Zoo-Freebies - Teachers Pay Teachers
Zoo Masks - Angel Fire
vteAdventist Adventurer Awards :
# Adventist Investiture Achievement Awards/Friend
## Friend

These are the requirements for the "Friend" Investiture Achievement Award. They are divided up into their respective categories:
* Personal Growth
* Spiritual Discovery
* Serving Others
* Making Friends
* Health and Fitness
* Nature Study
* Outdoor Living
* Honor Enrichment
# Adventist Investiture Achievement Awards/Friend/Making Friends

* Discover 10 qualities of being a good friend and share two that are most important to you.
* Fulfill requirements #1, #2, and #3 of the Christian Citizenship Honor.
          https://en.wikibooks.org/wiki/Adventist_Youth_Honors_Answer_Book/Outreach/Christian_Citizenship_%28United_States%29
# Adventist Investiture Achievement Awards/Companion
## Companion

These are the requirements for the "Companion" Investiture Achievement Award. They are divided up into their respective categories:
Personal Growth Spiritual Discovery Serving Others Making Friends Health and Fitness Nature Study Outdoor Living Honor Enrichment
# Adventist Investiture Achievement Awards/Friend/Serving Others

1. In consultation with your leader, plan ways and find opportunities to spend time being a friend with someone in need.
2. Spend at least four hours participating in projects that benefit the church or school.
* How I Helped (Please describe the Project below)
* A.
* B.
* C.
* D.
* E.
Advanced for Serving Others
1. Complete Friend requirements.
2. Bring someone who does not regularly attend church to a church program or activity.
# Friend / Spiritual Discovery
## Standard Requirements
### 1a. Memorize in order the New Testament books of the Bible and know the four areas into which the books are grouped

| Gospels | History | Epistles | Revelation / Prophecy |
| Matthew | Acts | Romans | Revelation |
| Mark | | 1 Corinthians | |
| Luke | | 2 Corinthians | |
| John | | Galatians | |
| | | Ephesians | |
| | | Philippians | |
| | | Colossians | |
| | | 1 Thessalonians | |
| | | 2 Thessalonians | |
| | | 1 Timothy | |
| | | 2 Timothy | |
| | | Titus | |
| | | Philemon | |
| | | Hebrews | |
| | | James | |
| | | 1 Peter | |
| | | 2 Peter | |
| | | 1 John | |
| | | 2 John | |
| | | 3 John | |
| | | Jude | |

### 1b. Demonstrate your ability to find any New Testament book
## 2. Memorize a Bible text for the following subjects

| * Prayer Matthew 6:9-13 Mark 1:35 1 Samuel 12:23 1 Thessalonians 3:10 | * Doctrine John 10:10 2 Timothy 3:15 Exodus 20:3-17 | * Behavior Luke 2:52 Luke 4:16 Ephesians 6:1 Psalms 51:10 Psalms 16:8 | * Salvation Eccleseastes 12:1 John 3:16 1 John 1:9 Ezekiel 33:11 John 17:15 |
| * Relationships Psalms 107:1 Psalms 103:13 Philippians 4:19 Isaiah 58:9-10 Psalms 84:1-2 | * Promises/Praise Proverbs 17:22 Proverbs 12:22 Philippians 4:4 Proverbs 6:6 Proverbs 28:14 | * Great Passages Psalms 23 Exodus 20:1-17 Matthew 5:3-12 Psalms 8:5-9 | |

## 3. Participate in a skit on the story about the life of Jesus such as

* Jesus in the temple at 12
* Jesus being tempted in the wilderness
* Jesus feeding the 5,000
* another favorite story of Jesus

## 4. Learn about the worldwide Advent Awakening (late 1700's to 1844) by identifying seven people and three events explaining why they are important.

Please visit our Seventh Day Adventist Church Pioneers page here on Wikibooks
http://en.wikipedia.org/wiki/Seventh-day_Adventist_Church_Pioneers
# A-level Computing/AQA/Problem Solving, Programming, Data Representation and Practical Exercise/Skeleton code/2013 Exam

The exam questions are very hard to predict and this site is by no means going to give you everything you need for the questions you'll sit. The most important thing you should do is learn how to program, and learn how to program well!
The exam is split into 4 sections that must be completed on a computer:

## Section A

<35 minutes> Theory Questions based on the material you have covered for Unit 1. For an overview of what this might include see the specification and this wikibook.
* Section A

## Section B

<25 minutes> Programming solutions to short problems, not based on the preliminary material or skeleton code.
* Section B

## Section C

<10 minutes> Theory questions about the preliminary material and skeleton code.
* Section C

## Section D

<50 minutes> Program solutions based around the preliminary code. The guidance below doesn't pretend to offer the actual questions that will be set in the exam, but by doing them you should hopefully get a better grasp of the code and be able to answer any questions thrown at you during the exam.
* Section D