A steel ball and a piece of clay have equal mass. They are dropped from the same height on a horizontal steel platform. The ball bounces back with nearly the same speed with which it hit. The clay sticks to the platform. Which object experiences the greater momentum change? (A) the ball (B) the clay change (C) Both experience the same momentum (D) there is no momentum change for either (E) more information is required

Answer: The ball (option A)

Explanation: change in momentum is defined by the formulae m (v - u) where m = mass of object, v = final velocity and u = initial velocity.

For the ball, it hits the ground and bounces back with the same speed, that's final velocity equals initials (v = - u)

Change in momentum = m (-u - u) = m (-2u) = m (-2u) = - 2mu

For the clay, it final velocity is zero since it sticks to the floor, hence (v = 0)

m (v - u) = m (0 - u) = - mu.

-2mu (change in momentum from the ball) is greater than - mu (change in momentum of clay)