Question

A stone.is.dropped a frieght of 20 m ?how long will a take to reach the ground?what will be its speed when it hits the ground

Answer 1

So

1/2m$v^{2}$=mgh

By Conservation of Mechanical Energy

v=$\sqrt{2gh}$

v=$\sqrt{20*10*2}$

v=20m/s

Hope so you understand the concepts ask if you have any doubts