ELECTRICITY

Power:
power = voltage x current
(current = 'I')

Voltage:
voltage = current x resistance

Charge:
charge = current x time
(charge = 'Q')

Energy:
energy = voltage x current

Efficiency % :
efficiency = (useful energy out / total energy in) x 100

GPE:
Gravitational potential energy = mass x gravity x height

Kinetic Energy :
kinetic energy = 0.5 x mass x velocity²