Question

A 0.20-kg tennis ball approaches a racket at 27 m/s. If it is in contact with the racket’s strings for 0.006 s, then rebound at 27 m/s, what is the average contact force between the ball and the racket?

Answer 1

When the ball rebounds, the momentum changes direction, but it is if the same magnitude. The average contact force is

$$F=\frac{∆p}{∆t}=\frac{2mv}{∆t}=1800\text N$$