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When playing tennis, Tina faces a ball coming toward her with a momentum of 0.70 ns. After she hits the ball, its momentum is 1.20 ns. If the time of contact between the racquet and the ball is 4.5 \times 10^{-2}4.5×10 ^−2

seconds, what is the force with which Tina hit the ball?

a. 42 newtons
b. 48 newtons
c. 51 newtons
d. 52 newtons

User Sayem
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1 Answer

5 votes

Final answer:

The force with which Tina hit the ball is calculated using the impulse-momentum theorem. The change in momentum is 0.50 ns, and with the time of contact being 4.5 × 10^-2 seconds, the force is approximately 11.11 N, which doesn't match any of the given options. This indicates a potential issue with the question or the options provided.

Step-by-step explanation:

The student is asking about the force exerted by Tina on a tennis ball during an impact, using principles from physics, specifically the concept of momentum. To find the force exerted, we can use the impulse-momentum theorem, which relates force, time of contact, and change in momentum of the tennis ball. We know that the momentum of the ball before Tina hit it was 0.70 ns, and after the hit, it was 1.20 ns. Therefore, the change in momentum (Δp) is 1.20 ns - 0.70 ns = 0.50 ns (where ns is the unit Newton-second).

The formula for impulse (J) is:

J = Δp = F ∙ t

Where F is the average force and t is the time of contact between the ball and racquet. Given the time of contact t = 4.5 × 10-2 seconds and the change in momentum (Δp) = 0.50 ns, we can solve for F:

F = Δp / t = 0.50 ns / (4.5 × 10-2 seconds) = 11.11 N

Therefore, the force with which Tina hit the ball was approximately 11.11 Newtons, which is not one of the answer choices provided, indicating that there may be a discrepancy in the provided answer choices or a typo/error in the question setup. The result needs to be revisited for accuracy.

User Aleksandr Ianevski
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