mia (acidstarz) wrote in exam_panic_zomg,
mia
acidstarz
exam_panic_zomg

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we were given this bunch of notes with the "bones" of our course, you guys might find it useful :)

Energy

Energy = Work Done = Force x distance moved in the direction of Force

Kinetic Energy (K.E.) = 1/2mv2  where m is mass and v is velocity (JOULES)

Potential Energy (P.E.) = mgh where m is mass, g is gravity and h is height (JOULES)

Power = Energy / time = Work done/Time (WATTS)

Efficiency = Power Out/Power In (Remember Pout over Pin) = Energy Out/ Energy In (per second)Multiply by 100 to get percent.


Heat Transfer

Conduction
* Metals, free electrons dominate
* Solids, domino effect on vibrations

Convection
* Heat --> Kinetic Energy --> Expansion
* Less dense rises

Radiation
*Electromagnetic Waves can travel in a vacuum
*Sun'slight is heat

Uses of expansion in everyday life --> Bimetallic strip in thermostats

Forces

Newtons Laws
* 1st Law = Law of inertia
* 2nd Law = Resultant Force = ma (with m being mass and a being acceleration)
* 3rd Law = Action & Reaction (every action has an equal and oppisite reaction)

Force --> Weight = mg   (g=10m/s on earth)

Density = mass/volume (kg/m3)

Hookes law - extension is directly proportional to load (Springs)
F =mg =K.e.)

Moments

Clockwise moment = anti-clockwise moment

Moment = Force x Distance from Pivot

Centre of Gravity / Mass = Point where the force of gravity acts.

Pressure = Force/Area (N/m2 = Pa)

* Liquids are not compressible therefore pass on the pressure applied.

Motion

Speed = Distance / Time           Velocity = Displacement/Time

Equations of motion (Triple Awars)
1. v = u + at
2. s = ut + 1/2at2
3. v2=u2 +2as

* In a displacement time graph the gradient (slope) = velocity

* In a velocity time graph the gradient = acceleration & the area under the line is the distance travelled.

Momentum = mass x velocity = mv (Ns=Kgm/s)

if abody movesin a circle then a force muct be applie to keep it moving in that circle. This is the CENTRIPETAL FORCE.

Ball on a string -->force is due to the tension in the string. if the string breaks the ball flies off at a tangent

F = mv2/r

Waves


Waves can be transverse or longitudinal.

frequency = number of waves per second (Hz [Hertz] )

Wave equation --> v=f(lambda)  lambda looks like an upside down y, I don't know how to do it on the computer)

* Sound is a longitudinal wave. A human can hear 20Hz --> 20KHz (or 15KHz if they are elderly)
* Sound cannot travel in a vacuum
* Frequency controls pitch, Amplitude controls loudness

*Light is part of the electromagnetic spectrum
* These waves travel at c= 3x108 m/s in a vacuum
* Light travels in straight lines --> this is what causes shadows.

Total Internal Reflection (TripleAward)
This is when light isreflected back into the glass because the angle of incidence = criticle angle and then the refracted angle = 90

White light is dispersed in the colours of the rainbow

(Red --> Orange --> Yellow --> Green --> Blue --> Indigo --
> Violet)

Electricity

I(amps) =Current = Change Q / CHange T

RESISTORS IN A SERIES ADDeg Resistance = 1/R1 + 1/R2 + 1/R3 etc etc

Resistors in parallel --> 1/R = 1/R1 + 1/R2 + 1/R3 etc

Ohms law --> V=IR

W = Energy =QV

Power = Energy/ Time =IV =V2/R = I2R

In a plug
*Green and Yellow is the EARTH wire and goes to the top pin
* Blue is the NEUTRAL wire and goes to the left
* Brown is the LIVE wire and goes to the right pin (or wherever the fuse is located)

Double Insulation is represented by a square inside a square.

Cost of electricity --> 1 unit = 1Kwhour


Earth and Space

Force of attraction= GM1M2 / r2




Want me to elaborate on/explain anything ?

Also, remember to look at this !

This community is well dead like.
Tags: crash course, physics
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