ap physics 1 impulse questions

Question

A 0.050 kg tennis ball approaches Vickey moving to the left at 10.0 m/s when Vickey hits it with a tennis racket being swung to the right. The magnitude of the force exerted on the ball by the racket as a function of time is shown in the figure above. What is the speed of the ball after being hit by the racket? (magnitude only)

(the graph is a force vs time graph in which the area is equal to 2000.

0.5 x 500 N x 8 seconds so 2000 is the change In momentum)

Answer 1

Your calculation for Impulse does not appear correct. A tennis racket would not be in contact with a tennis ball for 8 seconds. Perhaps 0.8 seconds, but not 8 seconds. Please double check.

First define your coordinate plane:

Notice v₁ is negative and F is positive.

The change in momentum is equal to the impulse.

The change in momentum (P) is P₂ - P₁ or mv₂ - mv₁ = m(v₂ - v₁)

v₁ = -10

m = 0.05

F is positive so impulse is positive = 2000 Ns

P₂ - P₁ = I

m(v₂ - v₁) = I

0.05(v₂ - (-10)) = (whatever the impulse turns out to be)

solve for v₂