Question

A boy drops a stone from a cliff , which reaches the ground in 20 seconds. Calculate the height of the cliff.

Answer 1

More suvat equations here, this time s=ut+1/2at^2 where s is the displacement, t is the time, and a is the acceleration.

So s=0*20+1/2*9.81*20^2
simplified: s=1/2*9.81*(20)^2
s=1962
The height of the cliff is 1962m