Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

A 0.140 kg baseball is dropped from rest. It has a speed of 1.20 m/s just before

ID: 1415219 • Letter: A

Question

A 0.140 kg baseball is dropped from rest. It has a speed of 1.20 m/s just before it hits the ground. It rebounds with a speed of 1.00 m/s. The ball is in contact with the ground for 0.0140 s. What is the average force exerted by the ground on the ball during that time? A. 22.0 N downwards B. 2.00 N downwards C. 2.00 N upwards D. 22.0 N upwards A 0.140 kg baseball is dropped from rest. It has a speed of 1.20 m/s just before it hits the ground. It rebounds with a speed of 1.00 m/s. The ball is in contact with the ground for 0.0140 s. What is the average force exerted by the ground on the ball during that time? A. 22.0 N downwards B. 2.00 N downwards C. 2.00 N upwards D. 22.0 N upwards A. 22.0 N downwards B. 2.00 N downwards C. 2.00 N upwards D. 22.0 N upwards

Explanation / Answer

Let downward direction be negative and upward be positive

vi = -1.2 m/s

vf = 1 m/s

change in momentum, p = m*(vf-vi)

= 0.140*(1 + 1.2)

= 0.308 kgm/s

t = 0.0140 s

F = change in momentum/time

= 0.308/0.0140

= 22.0 N

Since sign is positive, it will be upward

Answer: D