Physics Formulas

moment

Force x perpendicular distance from pivot

Power

Work done / time

Acceleration

final velocity-initial velocity/time

Force

Spring constant x extension

Work done

force x distance moved in direction of force

Momentum

mass x velocity

impulse

Change in momentum.
Force x time = Momentum(v-u)

kinetic energy

1/2 x mass x speed^2

gravitational potential energy

mass x gravitational field strength x height

Distance time graph

Gradient = speed

Speed time graph

Gradient = acceleration
Area = distance

Acceleration time graph

Area = velocity

Efficiency

(Useful power | energy output)/ (total power | energy input) x 100%

Force

mass x acceleration

pressure

(change in momentum/time)/area

Weight

Mass x gravitational field strength

moment

clockwise moment = anticlockwise moment
no resultant force

Boyle's Law

P1V1=P2V2 (temperature is constant)

specific heat capacity

Energy / mass x temperature change
(J/Kg°C)

Specific Latent Heat

energy / Δ mass (J/Kg)

Thermal Capacity

mass x specific heat capacity
Energy/ΔT (J/°C)

Energy

Power x time

Speed of a wave

wavelength x frequency (m/s)

speed of light in a vacuum

3 x 10^8 m/s

n (refractive index using speeds) =

speed of light in a vacuum/speed of light in material

n (refractive index using angles) =

sin i / sin r (rarer to denser)
sin r/ sin i (denser to rarer)

n (refractive index using critical angle)

1 / sin C

constants and variables of diffraction

frequency - constant
wavelength - constant
speed - constant

constants and variables of refraction

frequency - constant
speed - varies
wavelength - varies
(speed is directly proportional to wavelength)

Shallow and Deep Water Waves

Frequency - Unchanged
Speed - Increases (away from normal)
Wavelength - larger

Deep and shallow water waves

Frequency - Unchanged
Speed - Decreases (Towards normal)
Wavelength - smaller

total internal reflection

i > c

When r = 90°

i = C

Properties of electromagnetic waves

Wavelength Decreases
Frequency - Increases
Temperature of bodies emitting the waves - Increases
Amplitude - decreases

electromagnetic spectrum

radio waves,
microwaves,
infrared waves,
visible light,
ultraviolet waves,
x-rays,
gamma rays

Resistance

Voltage/current

Power

voltage x current

Energy

voltage x current x time

Power loss equation

Current^2 x resistance

Charge(Q)

current(I) x time(t)

Resistance with wire

Directly proportional to Length
inversly proportional to Diameter

Voltage

energy/charge

Transformer

N1 / N2 = V1 / V2 = I2 / I1

alpha beta and gamma with magnetic fields

alpha attracted to negative
beta attracted to positive
gamma unchanged

Series circuit

Rt= R1 + R2 +R3...
Vt= V1 + V2 +V3...
I is constant

Parallel circuit

1/Rt= 1/R1 + 1/R2 + 1/R3...
It = I 1 +I 2 + I 3...
V is constant

dc motor

Fleming's left hand rule

ac generator

Fleming's right hand rule

Current in a wire

Actual count

Reading in detector - Background radiation

alpha waves

beta particles

Instantaneous number

initial number/2(half life)

What can stop alpha beta and gamma