The Equations of Motion
If a body acceleratesuniformly, analysis of the motion of the body becomes muchsimplified. We can use any of five equations of motion:
(1)
(2)
(3)
(4)
(5)
where s=distance travelled,u=initial speed, v=final speed, a=acceleration and t=time.
Assuming (1) and (5), theothers are easily proved.
To prove (2) substitute (5)into (1)
To prove (3) rearrange (1)to give u=v-at and substitute into (5)
To prove (4) rearrange (1)to give
andrearrange (5) to give 
Multiplythe equations together:
so
The equations of motion areused by writing down which of
youhave and which you want to find. On this basis you can decide whichequation you need to use.
Suppose a car starts fromrest and accelerates to a speed of 10m/s in 20m. Find theacceleration
We look which of theequations has
Itis
