A ball of mass m falls vertically to the ground from a height h1 and rebound to a height h2. The change in momentum of the ball on striking the ground is
When ball falls vertically downward from height h1 its velocity →v1=−√2 gh1 and its velocity after collision →v2=√2 gh2
Change in momentum Δ→P=m(→v2−→v1)=m(√2gh1+√2gh2)