A 0.25 kg rubber bаll is thrоwn hоrizоntаlly аt a wall with a speed of 10.0 m/s. It bounces straight back with a speed of 8.0 m/s in the opposite direction. The ball is in contact with the wall for 0.015 s. What is the change in momentum of the ball? What is the magnitude of the average force exerted by the wall on the ball?