Question

A ball is dropped from cliff of a tower of height of 40 m what will be its velocity after falling 20 m

Answer 1

Using v^2 -u^2 = 2as

When ball is at 20 m,then v^2= 2×10×20 gives you v= 20m/s
When it is about to touch ground i.e. 40 m ,then v^2= 2×10×40 gives you v=√800m/s