Question

A person hits a tennis ball with a mass of 0.058 kg against a wall. The average component of the ball’s velocity perpendicular to the wall is 11 m/s, and the ball hits the wall every 2.1 s on average, rebounding with the opposite perpendicular velocity component. (a) What is the average force exerted on the wall? (b) If the part of the wall the person hits has an area of 3.0 m², what is the average pressure on that area?

a) 0.12 N; 0.04 Pa
b) 0.04 N; 0.12 Pa
c) 0.08 N; 0.08 Pa
d) 0.15 N; 0.05 Pa

Answer 1

To find the average force exerted on the wall when a tennis ball hits it, we can use Newton's second law. The average force is approximately 0.308 N. To find the average pressure exerted on the wall, we can use the formula pressure equals force divided by area. The average pressure is approximately 0.103 Pa.

Step-by-step explanation:

To find the average force exerted on the wall when a tennis ball hits it, we can use Newton's second law which states that force is equal to mass times acceleration. In this case, the mass of the ball is given as 0.058 kg. Since the velocity of the ball changes direction when it rebounds, the change in velocity is equal to twice the initial velocity, which is 2 * 11 m/s. The time interval between each rebound is 2.1 s.

Using these values, we can calculate the average force as follows:

F = m * (change in velocity / time interval)

F = 0.058 kg * (2 * 11 m/s) / 2.1 s

F ≈ 0.308 N

To find the average pressure exerted on the wall, we can use the formula pressure equals force divided by area. The area of the wall is given as 3.0 m².

Using these values, we can calculate the average pressure as follows:

P = F / A = 0.308 N / 3.0 m² ≈ 0.103 Pa