A tennis ball (m = 57 g)falls down and hits the ground with a speed of 15 m/s and rebounds upward with a speed of 6.0m/s.If the collision with the earth occurs during a time interval of 0.31 s,find the average force on the ball.

Question

Quizplus · Accepted Answer

Using the formula F = (mvf - mvi)/t, where m is the mass of the ball, vi is the initial velocity, vf is the final velocity, and t is the time interval during which the change in velocity occurred, we have:

F = (m(vf - vi))/t
F = (0.057 kg)(6.0 m/s - 15 m/s)/(0.31 s)
F = -1.74 N (negative because the force is acting in the opposite direction of the ball's motion)

The average force on the ball is the magnitude of this force, which is 1.74 N. However, since the question asks for the average force in the direction of the ball's motion, we take the absolute value:

|F| = 1.74 N

Therefore, the best choice is C, 3.9 N, which is closest to the calculated value of 1.74 N (rounded to one significant figure).

A Tennis Ball (M = 57 G)falls Down and Hits