How and why things move: Formulae

Some formulae will be given to you in the examination.  You will need to remember other formulae. In both situations you will need to know how to apply and use the formulae. Always (i) write down the formula, (ii) show your working, and (iii) give the answers with units.  You might find it easier to use symbols to remember these formulae

I need to remember these .....

momentum = mass × velocity


change of momentum = resultant force x time for which it acts


Work done = resultant force x distance moved


change in gravitational PE  =  weight      x    vertical height difference


kinetic energy =   ½   x  mass x    [velocity]2

Average speed  =  gradient of a distance-time graph

I will be given this formula:

Average speed   =   distance moved

                                     time taken