Question

a lump of clay and a rubber ball of identical mass are thrown at a wall with the same speed, which is true?
a. the clay and the ball experience the same change in momentum
b. the ball experiences a greater change in momentum than the clay
c. the clay experiences a greater change in momentum than the ball
d. it is not possible to determine

Explanation:

Step1: Define the formula for change in momentum

The formula for momentum is \(p = mv\). The change in momentum \(\Delta p=p_{f}-p_{i}\). Let the initial velocity of both (clay and ball) be \(v_{i} = v\) (towards the wall) and mass be \(m\).

Step2: Calculate change in momentum for clay

When the clay hits the wall, it sticks. So \(v_{f}=0\). Then \(\Delta p_{clay}=m\times0 - mv=-mv\) (magnitude is \(mv\))

Step3: Calculate change in momentum for rubber - ball

When the rubber - ball hits the wall, it rebounds. Assuming elastic - like collision (it bounces back with speed approximately \(v\) in the opposite direction). So \(v_{f}=-v\). Then \(\Delta p_{ball}=m(-v)-mv=- 2mv\) (magnitude is \(2mv\))

Answer:

B. the ball experiences a greater change in momentum than the clay