25. A ball of mass 0.40 kg moves in a direction at right angles to a wall. The ball
hits the wall at a speed of 9.0 m/s and rebounds at a speed of 6.0 m/s.
The contact time between the ball and the wall is 50 ms.
Calculate the average values of:
a. the acceleration of the ball during the collision with the wall
b. the force between the wall and the ball.
26. An air rifle pellet of mass 2.0 g is fired at an initial speed of 180 m/s into a
stationary block of clay and becomes embedded in the block. The average
force acting on the pellet from the block is 750 N.
a. Calculate:
1. the change in the momentum of the pellet
ii. the stopping time of the pellet in the clay block.
b. Estimate the distance that the pellet penetrated.
Outline why the answer in part b. is an estimate.