Question

A ball of mass ‘m’ falls vertically on the ground from a height ‘h’ and rebounds. If coefficient of
restitution between ball and ground is 1/2
then the magnitude of change in momentum of ball during collision with ground is

Answer 1

Given :

Mass of ball = m

Height = h

Coefficient of resolution = 1/2

To Find :

The magnitude of change in momentum

Solution :

• Velocity of ball = √2gh

• Initial velocity = √2gh

• Initial momentum of the ball = m√2gh

• Coefficient of resolution = Final velocity / initial velocity

• Final velocity = initial velocity/2= √2gh/2

• Final momentum = -m√2gh/2 (opposite direction)

• Change in momentum = Initial momentum - final momentum

                 = m√2gh + m√2gh/2

                 = 3m√2gh / 2

                 = (3/2)m√2gh

• The change in momentum of ball during collision is (3/2)m√2gh