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