Question

You throw a ball with a mass of 0.40 kg against a brick wall. It hits the wall moving horizontally to the left at -30m/s and rebounds horizontally to the right at 20m/s. Find the impulse of the net force on the ball during its collision with the wall.

Answer 1

$$\Delta p=m(v_f-v_i),$$ $$\Delta p=0.4\ kg\times(20\ \dfrac{m}{s}-(-30\ \dfrac{m}{s}))=20\ \dfrac{kg\times m}{s}.$$