A boy drops a stone from a cliff which reaches on the ground in B seconds. Calculate

(i) height of cliff


(ii) final velocity of the stone

Let H be the height of the cliff.


Now, ball is initially at rest


So, u = initial velocity = 0


a = acceleration = g


v = final velocity


t = B seconds


(i) From the equations of motion, we know that,





(ii) Now, we also know that,


v = u + at


v = 0 + gB


v = gB


18