Question

a ball is dropped from a height . if it takes 0.2s to cross the last 6m before hitting the ground, find the height from which it is dropped . take g=10m/s^2

Answer 1

 Use S = ut + ½ at2 where S=6m ,t=0.2s.a=10

you will get the value of u.

Now use v2 = u2 + 2as where v=u i.e the value which u got in the previous step and here u=0 as it is freely falling body.

Solve the eqn to get s.

Now total h=s+6m

calc time using t=(2h/g)1/2 .