# PHYSICS EQUATIONS

FORCES AND MOTION: average speed
average speed = distance moved / time
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FORCES AND MOTION: acceleration
acceleration = change in velocity / time taken ; a = (v-u)/t
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FORCES AND MOTION: unbalanced force
F=ma
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FORCES AND MOTION: weight
W=mg
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FORCES AND MOTION: momentum, mass and velocity
p=mv
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FORCES AND MOTION: force, change in momentum and time taken
force = change in momentum / time taken
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FORCES AND MOTION: moment
m=fd
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FORCES AND MOTION: Hooke's law
f is proportional to e
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FORCES AND MOTION: astronomy
orbital speed = 2пr / T
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ELECTRICITY: mains - power
P = IV
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ELECTRICITY: mains - energy transferred
E = IVt
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ELECTRICITY: energy and p.d. in circuits
V = IR
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ELECTRICITY: mains - charge
Q = It
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WAVES: wave speed
wavespeed = frequency x wavelength
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WAVES: frequency and time period
f = 1 / t
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WAVES: light - refractive index
n = sin i / sin r
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WAVES: light - critical angle and refractive index
sin c = 1 / n
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ENERGY: transfer - efficiency
efficiency = useful energy output / total energy input
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ENERGY: work and power - work done
W = fd
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ENERGY: work and power - GPE
GPE = mgh
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ENERGY: work and power - kinetic energy
KE = 0.5mv ²
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ENERGY: work and power - power and work done
P = W / t
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SOLIDS, LIQUIDS AND GASES: density
density = mass / volume
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SOLIDS, LIQUIDS AND GASES: pressure
p = F / A
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SOLIDS, LIQUIDS AND GASES: pressure difference
pressure = height x density x g
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SOLIDS, LIQUIDS AND GASES: pressure and temperature - gas
p1 / T1 = p2 / T2
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SOLIDS, LIQUIDS AND GASES: pressure and volume - gas
p1V1 = p2V2
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ELECTROMAGNETISM: electromagnetic induction - voltages and turns in a transformer
input (primary) voltage / output (secondary) voltage = primary turns / secondary turns; Vp / Vs = np / ns
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ELECTROMAGNETISM: electromagnetic induction - input power for 100% efficiency
input power = output power; VpIp = VsIs
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atomic number -2, mass number -4, + helium
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mass number +1, + electron
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## Other cards in this set

### Card 2

#### Front

acceleration = change in velocity / time taken ; a = (v-u)/t

#### Back

FORCES AND MOTION: acceleration

F=ma

W=mg

p=mv