3. Before starting this problem, review Conceptual Example 4.
Suppose that the hail described there bounces off the roof of the car
with a velocity of +15 m/s. Ignoring the weight of the hailstones, cal-
culate the force exerted by the hail on the roof. Compare your answer
to that obtained in Example 2 for the rain, and verify that your answer
is consistent with the conclusion reached in Conceptual Example 4.