Question

A ball comes back after an elastic collision with a wall. If initial momentum of the ball is P, the impulse on the wall after the collision is

• A. P
• B. 2P
• C. Zero
• D. -2P

Answer 1

The correct option is B 2P

Given the ball comes back.
hence, their is no change in the magnitude, the only change in the momentum of the ball is in its direction
initial momentum of ball $=$ P
final momentum $=$ $-P$
change in the momentum of the ball $=$ $-2\ast P$
change in momentum of the wall $=$ $-$ change in momentum of the ball
therefore impulse on the wall $=$ change in momentum of the wall $=$ $2\ast P$