Question

A bouncy rubber ball and a wet lump of clay, both of mass m, are thrown at a wall. Both strike the wall at speed v, but although the ball bounces off with no loss of speed, the clay sticks. 

What are the changes in momentum of the clay and ball, respectively? 

Answer 1

As you know the change in momentum

∆P=P2-P1. ...1

For ball P2 = mv (Since Velocity Magnitude is same only direction is opposite)

P1=m(-v) ( - due to opposite direction)

Put these value in equation 1

∆P=mv-m(-v) =2mv .

similarly

for clay

∆P=P2-P1

∆P=m(0)-m(-v)

∆P=mv

So Answer is

mv , 2mv (clay and ball respectively)