These will not be given to you
Velocity
|
v = x
t
|
v = velocity - m/s
x = displacement - m
t = time – s
|
Average speed
|
Av
speed = distance
time
|
|
Acceleration
|
a
= change in velocity
time
a
= (v – u)
t
|
a = acceleration – m/s2
v
= final velocity – m/s
u = final velocity – m/s
t – s
|
Force
|
F
= ma
|
F = Force – N
m = mass – kg
a = accln m/s2
|
Momentum
|
P
= m x v
|
P = momentum - kgm/2
m = mass –kg
v = velocity – m/s
|
Density
|
ρ
= m
V
|
ρ = density – kg/m3
m = mass – kg
V = volume m3
|
Work
|
W
= Fx
|
W = work – J
F = Force – N
x = distance – m
|
Kinetic energy
|
KE
= ½ mv2
|
KE – J
m = mass – kg
v = velocity – m/s
|
Gravitational
Potential
Energy
|
GPE
= mgh
|
GPE – J
m = mass – kg
g = gravitational field
strength – N/kg
h = vertical height – m
|
Weight
|
w
= mg
|
W = weight – N
m = mass – kg
g = gravitational field
strength – N/kg
|
Pressure
|
P
= F
A
|
P = pressure – Pa
F = Force N
A = Area – m2
|
Pressure in fluids
|
P
= hρg
|
P = pressure – Pa
ρ = density – kg/m3
h = vertical height – m
|
Moment
|
Moment
= Force x distance
|
Moment – Nm
|
Electric Charge
|
Q
= It
|
Q = charge – C
I = current – A
t = time – s
|
Ohm’s Law
|
V
= IR
|
V = voltage – V
I = current – A
R = resistance Ω
|
Electrical Power
|
P
= IV
|
P = power – W
I = current – A
V = voltage – V
|
Electrical Energy
|
E
= IVt
|
E = energy J
I = current – A
V = voltage – V
t = time – s
|
transformer
|
Vp
= Np
Vs Ns
Input power = output power
VpIp = VSIS
100% efficiency
|
Vp
= voltage in primary
Vs
= voltage in secondary
Np = number of turns in primary
Ns = number of turns in secondary
I = current
|
Wave equation
|
v
= fλ
|
v
= velocity m/s
f
= frequency – Hz
λ
= wavelength – m
|
Refractive index
|
n
= sin i
sin r
|
i
= angle of incidence
r
= angle of refraction
|
Critical angle
|
Sin
c = 1
n
|
Copied from the front of an examination papers
tso there is no excuse for not knowing the units of acceleration!
