A ball of mass 0.4 kg moving with uniform speed of 2 ms−1 strikes normally a wall and rebounds. Assuming the collision to be elastic and the time of contact of the ball with the wall as 0.4s, find the force exerted on the ball
4 N
F=ΔPΔt=[(0.4)(2)]−[(0.4)(−2)]0.4=4N