Physics Formulae

Current (Amps, A) = Charge (Coulombs, C) / Time (seconds, s)

Voltage (Volts, V) = Energy Transferred (Joules, J) / Current (Amps, A)

Potential Difference (Volts, V) = Current (Amps, A) X Resistance (Ohms)

Resistance (Ohms) = Potential Difference (Volts, V) / Current (Amps, A)

Power (Watts, W) = Energy Transferred (Joules, J) / Time (seconds, s)

Power Supplied (Watts, W) = Current (Amps, A) X Voltage (Volts, V)

Frequency (Hertz, Hz) = 1 / Period (second, s)

(1 period = time taken for one complete wave)

Speed (metres/second, m/s) = Distance (metres, m) / Time (seconds, s)

Acceleration (metres/second squared, m/s2) = Change in Speed (metres/second, m/s) / Time (seconds, s)

(This is the SAME formula for deceleration, just put a '-' in front of your answer)

Velocity (metres/second, m/s) = Speed in a specific direction

Resultant Force (Newtons, N) = Mass (kilograms, kg) X Acceleration (metres/second squared, m/s2)

Weight (Newtons, N) = Gravitational Field Strength (Newtons/kilograms, N/kg) X Mass (kilograms, kg)

Momentum (kilogramsmetres/second, kgm/s) = Mass (kilograms, kg) X Velocity (metres/second, m/s)

Impact Force (Newtons, N) = Change in Momentum (kilogrammetres/second, kgm/s) / Time [length] of Collision (seconds, s)

Kinetic Energy (Joules, J) = 1/2 X Mass (kilograms, kg) X Velocity SQUARED (metres/secondsquared, m/s2)

(Remember to square only the velocity, and don't forget the '1/2'!)

Work Done (Joules, J) = Force (Newtons, N) X Distance Travelled (metres, m)

• Always include the units in your answer - even if you get it wrong, you'll get a mark for the correct unit.
• Make sure you're using the right capital and small letters in units - they won't give you a mark for a small 'a' if you're talking about Amps, it has to be a big 'A'!
• Show how you're working things out - if you get the wrong answer, you may get a mark for using the right formula and substituting in the right bits of information.
• Read the question - some units might need to be converted (eg. grams to kilograms) so the formula works.
• Some of the hard formulae are on the paper, but it's worth knowing them all so you know how they work and what units they use, as these aren't given).

Good luck!