Question

You throw a bouncy rubber ball and a wet lump of clay, both of mass m, at a wall. Both strike the wall at speed v, but while the ball bounces off with no loss of speed, the clay sticks. What is the change in momentum of the clay and ball, respectively?

1. mv; 0
2. mv; mv
3. 0; mv
4. 0, 2mv
5. mv; 2 mv

Answer 1

5. mv, 2mv

Step-by-step explanation:

for clay :

initial momentum = P_i = - mv

final momentum = P_f = 0

change in momentum = Pf - Pi = 0 - (- mv) = mv

for ball :

initial momentum = P_i = - mv

final momentum = P_f = mv

change in momentum = Pf - Pi = mv - (-mv) = 2mv

so mv and 2mv are the change in momentum of the clay and ball, respectively