Question

When a golf ball is dropped to the pavement, it bounces back up. (a) Is a force needed to make it bounce back up? (b) If so, what exerts the force?

Short answer

(a) Yes, as the momentum changes, a force is needed to make the ball bounce back.

(b) Pavement exerts the impulsive force.

Step-by-step solution

Step 1. Understanding the relationship between change in momentum and force

According to Newton’s second law, the rate of change of momentum is equal to the force applied.

Step 2. Analysing the bouncing back of the ball

According to Newton’s second law of motion, we know that rate of change of momentum is equal to the amount of force applied.

Since the ball bounces back, its momentum changes (as momentum is a vector quantity, the change in the direction of velocity will result in a change in momentum).

Thus, a force is needed to be applied to achieve this change in momentum.

Step 3. Analysing the force being applied

As the ball hits the pavement surface, the surface exerts an impulsive normal force in the upward direction, and thus it starts moving upward.