A 3.56-kg steel ball strikes a massive wall at 10.0 m/s at an angle of θ = 60.0° with the plane of the wall. It bounces off the wall with the same speed and angle (see the figure below). If the ball is in contact with the wall for 0.180 s, what is the average force exerted by the wall on the ball?

2 answers

a = (Vf - Vo) / t,
a = (0 - 10) / 0.180 = -55.56m/s^2.

The force exerted by the wall is equal to and opposite the force exerted by the ball:

F = -ma = -3.56 * (-55.6) = 198N.
henry is incorrect