Question

drive Newton third equation of motion

Answer 1

Let a body start with an initial velocity 'u' and attain a velocity 'v' in 't' seconds . Let the body move with uniform acceleration 'a' and let 's' be the distance travelled during the time of 't' seconds
Average velocity = v+u/ 2
Distance travelled = average velocity x time
s = (v+u/2) x t
v + u = 2s/t .......( 1 )
We know that v+u = t
v-u = at ........( 2 )
Multiplying equation (1) and (2) , we get
(v+u) (v-u) = 2s/t x at
v^2 - u^2 = 2as
v^2 = u^2 + 2as