Question

A ball is dropped vertically from rest at a height of 12 m. After striking the ground, it bounces to a height of9m.what fraction of kinetic energy does it
loose on striking the ground

Answer 1

suppose the ball is falling from h height, now apply newton's of motion

v^2 -u^2= 2as since it is falling from rest so we have u=0 and a=g

we have v=√(2gh)

put h=12 and then h=9 find kinetic energies for both and then calculate

[(k.e)initail - (k.e.)final ]/ (k.e ) initial

u get ur ans 1/4