OpenLLM-France/wikimedia huggingface dataset:
# Physics Study Guide/Standing waves

| Units | Linear Motion | Force | Momentum | Normal Force and Friction | Work | Energy |
| Torque & Circular Motion | Fluids | Fields | Gravity | Waves | Wave overtones | Standing Waves | Sound |
| Thermodynamics | Electricity | Magnetism | Optics |
| Physical Constants | Frictional Coefficients | Greek Alphabet | Logarithms | Vectors and Scalars | Other Topics |

# Standing waves

Wave speed is equal to the square root of tension divided by the linear density of the string.
* μ = m/L
Linear density of the string is equal to the mass divided by the length of the string.
* λ$_{max}$ = 2L
The fundamental wavelength is equal to two times the length of the string.

## Variables

* λ: wavelength (m)
* λ$_{max}$: fundamental wavelength (m)
* μ: linear density (g/m)
* v: wave speed (m/s)
* F: force (N)
* m: mass (kg)
* L: length of the string (m)
* l: meters (m)

## Definition of terms

* Tension (F): (not frequency) in the string (t is used for time in these equations). Units: newtons (N)
* Linear density (μ): of the string, Greek mu. Units: grams per meter (g/m)
* Velocity (v) of the wave (m/s)
* Mass (m): Units: grams (g). (We would use kilograms but they are too big for most strings).
* Length of the string (L): Units: meters (m)
Fundamental frequency: the frequency when the wavelength is the longest allowed, this gives us the lowest sound that we can get from the system.
In a string, the length of the string is half of the largest wavelength that can create a standing wave, called its fundamental wavelength.
# Physics Study Guide/Purpose
## Purpose of Physics

The aim of the study of physics is to understand the natural world, in its broadest and most fundamental sense. By understanding it, we hope to be able to explain and predict (typically through the mathematics that are developed) and ultimately modify (oftentimes through resulting technology) events that occur. Physics deals with everything that happens in this Universe, tries to understand it and provides the root cause for the same in a logical manner.
# Physics Study Guide/Scientific Method
## Scientific Method

In order to uncover these 'laws of nature', physics (like all science) relies on a deliberately-structured process of
* observe a natural phenomenon, (for example thanks to an experimentation)
* creating a theory or model,
* testing the theory or model,
* adjusting the theory or model based on the results of the test,
* and repeating the above process with the adjusted theory or model.
This process is known as the 'scientific method'. Most curriculums thus incorporate elements of both theory (principally, what laws others have found in the past) and practical (how to undertake experiments and observations).
# DESCRIPTION:

Returns TRUE if a file or URL is a directory.
DIR? is a function value.

# ARGUMENTS

* target -- (Type: file url)

# (SPECIAL ATTRIBUTES)

* catch
# DESCRIPTION:

Computes the resulting, negotiated key from a private/public key pair and the peer's public key.
DH-COMPUTE-KEY is a native value.

# ARGUMENTS

* obj -- The DH key object (Type: object)
* public-key -- Peer's public key (Type: binary)
# DESCRIPTION:

Returns a copy of the path turned into a directory.
DIRIZE is a function value.

# ARGUMENTS

* path -- (Type: file string url)
# DESCRIPTION:

Wait for a block of ports. As events happen, dispatch port handler blocks.
DISPATCH is a function value.

# ARGUMENTS

* port-block -- Block of port handler pairs (port can be timeout too). (Type: block)
# DESCRIPTION:

Display the REBOL viewtop
DESKTOP is a function value.

# ARGUMENTS

* url -- (Type: url file any-type)

# REFINEMENTS

* /only -- Only if prefs/desktop option says so
# DESCRIPTION:

Generates a new DH private/public key pair
DH-GENERATE-KEY is a native value.

# ARGUMENTS

* obj -- The DH key object (Type: object)
# DESCRIPTION:

Return the difference of two data sets.
DIFFERENCE is a native value.

# ARGUMENTS

* set1 -- First data set (Type: series bitset date)
* set2 -- Second data set (Type: series bitset date)

# REFINEMENTS

* /case -- Uses case-sensitive comparison.
* /skip -- Treat the series as records of fixed size
** size -- (Type: integer)
# DESCRIPTION:

Returns the error value as an object.
DISARM is a native value.

# ARGUMENTS

* error -- (Type: error)
# DESCRIPTION:

Converts tabs in a string to spaces. (tab size 4)
DETAB is a native value.

# ARGUMENTS

* string -- (Type: any-string)

# REFINEMENTS

* /size -- Specifies the number of spaces per tab.
** number -- (Type: integer)
# DESCRIPTION:

Creates a key object for DH.
DH-MAKE-KEY is a native value.

# REFINEMENTS

* /generate
** length -- Key length (Type: integer)
** generator -- Generator number (Type: integer)
# Pinyin/Blue

Blue
Blue, represent wisdom and beauty, the symbol of perpetuality, peaceful and wide.
Having the imagery of ration and accuracy; courage, coolness and ration, the meaning of never giving up.
larnseh
larnseh, daihbiaao zhihhuih her meeilih, yoongherng d xiahngzheng, anxiarng her guaangkuoh.
juhyoou
liizhih, zhuunqueh d yihxiahng; yoongqih, leengjihng, liizhih, yoongbuyarnqih d harnyih.
# Pinyin/Blindness

Blindness is the inability to see. The leading causes of chronic blindness include cataract, glaucoma, age-related macular degeneration, corneal opacities, diabetic retinopathy, trachoma, and eye conditions in children (e.g. caused by vitamin A deficiency).
Age-related blindness is increasing throughout the world, as is blindness due to uncontrolled diabetes. On the other hand, blindness caused by infection is decreasing, as a result of public health action. Three-quarters of all blindness can be prevented or treated.
Mángzhèng jiùshì wú-shìjué. Mànxìng mángzhèng de shǒuyào yuányīn bāokuò báinèizhàng, qīngguāngyǎn, niánlíng-xiāngguānxìng huángbān tuìhuà, jiǎomó hùnzhuó, tángniàobìng shìwǎngmó-bìngbiàn, shāyǎn hé értóngqī yǎnjí (lìrú, yóu wéishēngsù A quēfázhèng zàochéng de yǎnjí).
Yǔ niánlíng yǒuguān de mángzhèng tóng bùjiā kòngzhì de tángniàobìng yǐnqǐ de mángzhèng yīyàng, zài shìjiè gèdì bùduàn zēngduō. Lìngyī fāngmiàn, gǎnrǎn yǐnqǐ de mángzhèng zhújiàn jiǎnshǎo, zhè shì yóuyú cǎiqǔle gōnggòng wèishēng xíngdòng. Sì fēnzhī sān de mángzhèng shì kěyǐ yùfáng huò zhìliáo de.
# Pinyin/Own

See also
# Pinyin/Owner

See also
# Pinyin/Oxidation

See also
# Pinyin/Oxygen

See also
# Pinyin/Painting

See also
# Pinyin/Pacific Ocean

Search Pacific
Search ocean
The Pacific Ocean borders Asia and Oceania to the west, the Americas to the east, the Southern Ocean to the south, and the Arctic Ocean to the north. It is the largest ocean and it covers 1/3 of the surface of the Earth.
Taihpirng Yarng xibuh yuu Yahzhou her Dahyarng Zhou, dongbuh yuu Meeizhou, narnbuh yuu Narnbing Yarng, beeibuh yuu Beeibing Yarng xiangliarn; shih zuih dah d haaiyarng, zhahn Dihqiur biaaomiahn d 1/3.
# Pinyin/Pain

See also
Pain
When without hope, pain is a long journey, so long, so tired.
When lonely, pain is a person's meeting, in the beginning is one own, in the end is one own.
When I am in difficulty, pain is an endless desert, I want to leave, yet cannot find exit.
When I am confused, pain is like endlessly dividing cells, when one thing is solved, another thing is beginning to generate.
tohngkuu
wurwahng shir, tohngkuu shih mahncharng d xirngcherng, rurcii charngyuaan, rurcii pirleih.
gudan shir, tohngkuu shih 1'g rern d juhhuih, kaishii shih zihjii, jiershuh yeeshih zihjii.
kuhnnarn shir, tohngkuu shih meir jihntour d shamoh, woo xiaang lirkai, queh zhaaobudaoh chukoou.
kuhnhuoh shir, tohngkuu shih buduahn fenlieh d xihbao, jieejuer le zheh'g, nah'g youh kaishii chaansheng.
# Practical Electronics/Parallel LC
## Summary

| Circuit | Symbol | Series | Parallel |
| LC | | | 200 |
| Impedance | Z | $Z_{t}=\omega L+{\frac {1}{\omega C}}={\frac {\omega ^{2}LC+1}{\omega C}}$ | $Z_{t}={\frac {\omega L}{\omega ^{2}LC+1}}$ |
| Resonance Frequency | $\omega =\omega _{o}$ when $Z_{L}=Z_{C}$ | $\omega L={\frac {1}{\omega C}}$ $\omega _{o}={\sqrt {\frac {L}{C}}}$ | $\omega L={\frac {1}{\omega C}}$ $\omega _{o}={\sqrt {\frac {L}{C}}}$ |
| Voltage | V | $V=L{\frac {dI}{dt}}+{\frac {1}{C}}\int Idt$ | $I={\frac {1}{L}}\int Vdt+C{\frac {dV}{dt}}$ |
# Practical Electronics/Plugins

Plug-in modules, or plugins are small electronic modules that fulfill a (usually simple) function and are capable of being plugged directly into a breadboard. Their purpose is to allow common parts of a circuit to be "plugged in" to reduce time spend breadboarding common parts. Common plugins are astables, switch debouncers, etc. They can be highly customised, and can be as simple or as advanced as you like.

## Construction

They are often made from stripboard and use 0.1" headers to make the connection to the breadboard. These headers are usually parallel to the stripboard, so the plugin stands vertically.
They are usually made as small and narrow as possible to avoid making unnecessary clutter on the breadboard. This means that resistors are often mounted "vertically" to save space, at the expense of ruggedness. Beware of this when inserting and removing plugins, as these components can easily be damaged or damage the track they are soldered to.

### Modifying the headers

The least expensive headers available are the straight variety. They cost a few pence each for headers with only a few pins, to up to about 50 pence each for up to 15 pins.
To make the plugins, these need a 90° bend in them. This is best done by using a pair of long-nosed pliers to bend the shorter end (the end normally put through the board) over towards the front of the header (the side without the backing plate). The length the pins come at is ideal for this application, so they do not need pushing of pulling through the plastic body yet.
When the required pins are bent over (you may not need all of the pins on a given header), then you can push them through the body so that only half the previous length remains above the plastic. Then, place the bent ends through the holes (they should project about 1 mm past the copper strips), and solder in place. Use the pliers to pull off the plastic body, and discard.

## Plugin plans
### Power Supplies

* 5V 1A Regulated Power Supply

### Signals and Amplification

* 555 Astable. Includes optional mark-space variance.
* 1Hz Crystal Oscillator. Uses a 32.768KHz crystal to provide a precise 1Hz output to drive timers, etc.
* Audio Amplifier. Good for listening to signals.

### Input

* De-bounced tact switch

### Decoding, DACs, ADCs

* R2R DAC. 8-Bit, but can be easily expanded.

## further reading

* "switch debounce" circuits
* another "switch debounce" circuit
# Practical Electronics/Plugins/1Hz Oscillator

This plugin uses a quartz oscillator which uses a crystal (X1), amongst other components to give a 32,768Hz (32,768=2$^{15}$) output. This is input to a 4020 14-Stage Ripple Counter, which divides this signal down by 2$^{14}$ to a 2Hz signal. This 2Hz signal is then halved in frequency using a JK flip-flop (4027) configured as a toggle flip-flop. The output from this is used as the 1Hz signal.
Both the 1Hz and 2Hz signals are taken as outputs, as the faster 2Hz signal is sometimes useful for clocking circuits at a visible speed, without going too slowly.
Below is the stripboard layout for the plugin. The dimensions of the stripboard are 12x23 holes. An LED and current-limiting resistor have been added to the 1Hz output to provide a visual indicator. This can be omitted without affecting the performance of the circuit. R2 may need to be mounted around D1, as there is very little space for it.
The parts lift below assumes a power supply of 9V. If a different voltage is used, it is possible that the LED current-limiting resistor (R2) must be changed and the oscillator may need adjustment as well.
Parts List :
| Ref. | Component |
| R1 | 1M Resistor, 1/4W |
| R2 | 470R Resistor, 1/4W (unless non-standard LED is used) |
| C1 | 100pF Ceramic Capacitor |
| C2 | 10pF Ceramic Capacitor |
| D1 | LED |
| X1 | 32,768Hz Quartz Crystal |
| IC1 | 40106 Schmitt Inverter IC |
| IC2 | 4020 14-Stage Binary Ripple Counter |
| IC3 | 4027 Dual JK Flip-flop |

## Variations

* Any of the 4020 outputs can be used as the final output, so it could be a 4Hz oscillator, or 16Hz or even 32,768Hz. The JK flip-flop would not be necessary in this case.
# Practical Electronics/Perfboard

There are many types of prototyping boards.
The vast majority of such boards are perforated at 0.1 inch (2.54mm) pitch (one hole each 0.1 inch/2.54mm) both horizontally and vertically (also called "tenth inch spacing"), made out of either "synthetic resin bonded paper" or fiberglass, and have some kind of copper pattern on one or both sides of the board.
Perhaps the most popular pattern is the "stripboard" -- which has wide strips of copper running one way all the way along one side of the board, but no copper on the other side. However, this type of board (and perfboards in general) will require soldering for the circuits to be able to function properly.
The other common type of prototype boards is the solder-less prototyping board also known as a breadboard.
* close up of unused Veroboard
* buzzer made using stripboard
* Because the strips (copper traces on the solder side) run left-and-right, the components (on the component size) usually run up-and-down.
* component side of AM receiver
* solder side of same AM receiver. DIP integrated circuits usually require traces to be cut between their 2 rows of pins
* Complex circuits, such as Dolby SR, have been built on stripboard.
* close up of unused "3-Hole Solder Pad" prototyping board, also called "TriPad"
* simple circuit using stripboard (component side)
* Breadboard
* Longer breadboard

## Further reading

* Open Circuits: stripboard
* Commons Wikimedia: gallery of stripboard images
* Wikipedia: stripboard
* Wikipedia: perfboard
* Wikipedia: Veroboard
# Practical Electronics/Preferred Values

Preferred values are a series of numbers between a power of ten and the next, each of which has a fixed ratio with the previous number. For more information, see the section in resistors. Commonly, the E12 is used for resistors, and the E6 series is used for capacitors, although if you use more accurate components, different systems may be used.
The E-series of preferred values are as follows:
# Practical Electronics/Relays
## Relay

Relay is an Electromagnetic Switch that can open and close circuit through Electromagnetic Force

## Construction

A relay is an electrically operated switch. Many relays use an electromagnet to operate a switching mechanism mechanically, but other operating principles are also used. Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuits), or where several circuits must be controlled by one signal. The first relays were used in long distance telegraph circuits, repeating the signal coming in from one circuit and re-transmitting it to another. Relays were used extensively in telephone exchanges and early computers to perform logical operations.

## Reference

* Relay
# Practical Electronics/Parallel RL
## Summary

| Circuit | Symbol | Series | Parallel |
| RL | | An RL parallel circuit |
| Impedance | Z | $Z_{t}=R+\omega L$ | $Z_{t}={\frac {\omega RL}{R+\omega L}}$ |
| Voltage | V | $V=IR+L{\frac {dI}{dt}}$ | $I={\frac {V}{R}}+{\frac {1}{C}}\int Vdt$ |
| Current | I | ${\frac {dI}{dt}}=(V-IR){\frac {1}{L}}$ | $\int Vdt=C(I-{\frac {V}{R}})$ |
| Phase Angle | I | tan θ = $\omega {\frac {L}{R}}$ = 2πf ${\frac {L}{R}}$ f = (Tanθ/2π)${\frac {R}{L}}$ t = (2π/Tanθ)${\frac {L}{R}}$ | tan θ = $\omega {\frac {L}{R}}$ = 2πf ${\frac {L}{R}}$ f = (Tanθ/2π)${\frac {R}{L}}$ t = (2π/Tanθ)${\frac {L}{R}}$ |
# Practical Electronics/Parallel RLC
## Summary

| Network | Symbol | Series RLC | Parallel RLC |
| Network | | | |
| Impedance | Z | $Z=(j\omega )^{2}+(j\omega ){\frac {R}{L}}+{\frac {1}{LC}}$ | $Z=(j\omega )^{2}+(j\omega ){\frac {1}{RC}}+{\frac {1}{LC}}$ |
| Roots | λ | λ = $-\zeta \pm {\sqrt {\zeta ^{2}-\omega _{o}^{2}}}$ | λ = $-\zeta \pm {\sqrt {\zeta ^{2}-\omega _{o}^{2}}}$ |
| I(t) | Ae$^{λ1t}$ + Be$^{λ2t}$ | Ae$^{λ1t}$ + Be$^{λ2t}$ | Ae$^{λ1t}$ + Be$^{λ2t}$ |
| Damping Factor | $\zeta$ | $\zeta ={R \over 2L}$ | $\zeta ={1 \over 2RC}$ |
| Resonant Frequency | $\omega _{o}$ | $\omega _{o}={1 \over {\sqrt {LC}}}$ | $\omega _{o}={1 \over {\sqrt {LC}}}$ |
| Band Width | $\Delta \omega =2\zeta$ | ${R \over L}$ | ${1 \over CR}$ |
| Quality factor | $Q={\omega _{o} \over \Delta \omega }={\omega _{o} \over 2\zeta }$ | $Q={L \over R{\sqrt {LC}}}={1 \over R}{\sqrt {L \over C}}$ | $Q={CR \over {\sqrt {LC}}}={R}{\sqrt {C \over L}}$ |
# Practical Electronics/Plugins/Astable

This plugin consists of a single 555 Astable. This plugin is very versatile, and can be used for any number of things, but it often is used to give a clock to run a circuit. The plugin below gives a pulse of about 2Hz with a very low mark-space ratio. The circuit diagram is given below.
This circuit obeys the following formulae with regards to its frequency and mark space ratio.
       $f={\frac {1.44}{\left(R_{1}+R_{2}\right)\times C}}$.
       This is different to the design equation for the standard 555 Astable. (R$_2$ instead of 2R$_2$)
       ${\mbox{High time}}=0.69R_{1}\times C$
       ${\mbox{High time}}=0.69R_{2}\times C$
       ${\mbox{Mark-space ratio}}=R_{ms}={\frac {R_{1}}{R_{2}}}$
The values below give a frequency of about 2Hz, with a mark-space ratio of about 1:50.
The stripboard layout is as shown below with a component list.
| Ref. | Component |
| IC1 | 555 Timer IC |
| R1 | 10K Resistor |
| R2 | 330K Resistor |
| C1 | 2.2μF Capacitor |
| D1 | 1N4148 Signal Diode |

## Variations
### Enable pin

To give this plugin an enable pin, replace the wire link from Pin 4 to +V with a 10K resistor going from Pin 4 to ground (Pin 1). Then add a header pin to Pin 4. A high signal on this pin will cause the astable to function, a low will disable it, locking the output low.
# RUP - IBM Rational Unified Process
## Table of Contents

* Introduction
* Agile methodologies
* Phases
* Disciplines or Workflows
# RTEMS for Embedded Software Developers/Using the RTEMS Addon Packages

This chapter will cover:
* Using the existing RTEMS Addon Packages
* Adding to the RTEMS Addon Packages
# RTEMS for Embedded Software Developers/RTEMS Addon Packages

Review using the existing RTEMS Addon Packages. The make -f and the example executables.
Next move onto adding some packages.
Limit selections easier libraries to build confidence, such as, Berkely Database.
Briefly discuss Makefile.in rules.
Reference: http://www.rtems.com/wiki/index.php/RTEMS_Add-On_Packages
# RTEMS for Embedded Software Developers/RTEMS Managers

Cover only the managers not already covered. Hard to list until previous chapters are written. Some may be:
* Message Manager
* Event Manager
* Partition Manager
* Region Manager
* Dual-Ported Memory Manager
* I/O Manager
* Fatal Error Manager
* Barrier Manager
* User Extensions Manager
* Multiprocessing Manager
* Stack Bounds Checker
Try to cover these as soon as reasonable (before this chapter, if it can make sense) in the text.

## POSIX Threading API

Although the classic API was written first, POSIX is a modern, and widely used, standard for operating systems development (cite). RTIED is also a standard, but primarily for embedded development. So POSIX will be discussed first.
* POSIX Example 1: discuss what functionality it's testing, why that functionality is needed, and how to extend it.
* POSIX Example 2: discuss what functionality it's testing, why that functionality is needed, and how to extend it.
* POSIX Example 3: discuss what functionality it's testing, why that functionality is needed, and how to extend it.
* POSIX Scheduling Report: discuss what functionality it's testing, why that functionality is needed, and how to extend it.

## classic api: handling signals, and periodic tasks

Why handle tasks using signals, absolute periods, rate monotonic periods, and relative periods
What are signals, absolute periods, rate monotonic periods, and relative periods
Now that we've touched on scheduling, we will extending the example by using ...

## Blink Light Emitting Diode (LED): more on handling signals, and periodic tasks

Many sub-examples... apply a pedagocal order... cover these in depth... may need to turn into its own chapter...
* complex1
* delay
* event_server
* msg_server
* posix_cond_server
* posix_delay_nanosleep
* posix_delay_sleep
* posix_mutex_server
* ratemon1
* ratemon2
* ratemon_cond_server
* sem_server
* timeout_event
* timer
* timer_server

## Scheduling Priorities: Sched Sim

* Discuss why use scheduling priorities
* Discuss what scheduling priorities are
* Discuss how to use scheduling priorities
* The example will be extended using rtems-schedsim
# Pinyin/Vocal Cord

Vocal cord is an organ in the throat for making sound.
shengdaih shih hourlorng fasheng d qihguan.
# Pinyin/Vitamin E

Search Pinyin vitamin
# Pinyin/Vitamin C

Search Pinyin vitamin
Search Pinyin vitamin C
# Pinyin/Vitamin P

Search Pinyin vitamin
# Pinyin/Voluntarily

See also
# Pinyin/Vitamin D

Search Pinyin vitamin
Search Pinyin vitamin D
# Pinyin/Wait

See also
# Pinyin/Waiting

Special:search/waiting prefix:Pinyin/
Waiting
Waiting, a flower blossoms, the rising of the sun, the appearance of a smile.
I wait quietly, a person's smile, a person's shoulder, accompanying me through lifetime.
deengdaih
deengdaih, 1-duoo hua d kaifahng, 1'g taihyarng d shengqii, 1'g weixiaoh d chuxiahn.
woo mohmoh dy deengdaih, 1'g rern d weixiaoh, 1'g rern d jianbaang, yuu woo gohngduh rernsheng.
# Pinyin/Volume

Volume is the amount of space that an object or a substance fills.
tiiji shih wuhtii huoh wuhzhih suoo zhahn kongjian d liahng.