General Physics
Formula in Symbols Formula
in Words
v = d / t speed
= total distance / total time
w = m x g weight
= mass x acceleration of gravity
a = v / t acceleration
= change in speed / change in time
d = m / v density
= mass / volume
F = m x a force
= mass x acceleration
x = k x F extension
= a constant x load
W = F x d work
= force x distance
p.e. = m x g x h potential
energy = mass x acceleration of gravity x height
k.e. = ½ x m x v2 kinetic
energy = ½ x mass x velocity squared
e = Eout / Ein x 100% energy efficiency = energy output / energy input x 100%
E = W energy
used = work done
E = m x c2 energy
of a nuclear reaction = mass x speed of light squared
P = E / t power
= energy / time
Physics of Waves
Formula in Symbols Formula
in Words
c = f x l speed
of a wave = frequency x wavelength
i = r angle of
incidence = angle of reflection
n = sin i / sin r index
of refraction = sine of incident angle / sine of refracted angle
Electricity and Magnetism
Formula in Symbols Formula
in Words
I = Q / t current
= charge / time
R = V / I resistance
= potential difference / current
R = k x l / A resistance
= a constant x length / cross sectional area
R = R1 + R2 resistances
in series add together
1 / R = 1 / R1 + 1 / R2 reciprocals
of resistances in parallel add together
I = I1 + I2 currents
in parallel add together
Iin =
Iout total current into a point =
total current out of a point
V = V1 + V2 voltage
of source = sum of all voltage drops in a circuit
P = I x V power
used in an electric circuit = current x voltage
E = I x V x t energy
used in an electric circuit = current x voltage x time
Vp = Np voltage
in primary coil = number of turns in primary coil
Vs = Ns voltage in
secondary coil number of turns in secondary coil
Vp x Ip = Vs x Is power
in primary coil = power in secondary coil (for a perfect transformer)
Geometry
Formula in Symbols Formula
in Words
a = s2 area
of a square = length of side squared
a = l x w area
of a rectangle = length x width
a = ½ x b x h area
of a triangle = ½ x base x height
a = p x r2 area
of a circle = Pi x radius squared
v = s3 volume
of cube = length of side cubed
v = l x w x h volume
of cuboid = length x width x height
v = p x r2 x h volume
of cylinder = Pi x radius squared x height
You should be able to solve equations with three
variables for any variable.
For example, if a = b x c, then b = a / c and c =
a / b.
Formulas in bold are for core. Other formulas are extended, but they also
help for many core questions.
