- #1
danyork
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Homework Statement
Here is the question I'm trying to answer:
A tennis player hits a 1.45 kg tennis ball with a racket of mass 2.5 kg. If he hits the ball with a velocity of 7.5 m/s and then stops, what impulse did he imply on the ball? What is the ball’s velocity?
Homework Equations
Δpball = -Δpracket = mvi - mvf
ma initialva initial + mb initialvb initial = ma finalva final + mb finalvb final
The Attempt at a Solution
I was able to determine the impulse on the ball as 2.5 * 7.5, which is 18.75 kg m/s (ignoring sig figs for now). What I'm stuck on is how to determine the balls final velocity without the problem stating the initial velocity. Should I assume the initial is 0 m/s (this seems wrong). I'm thinking there has to be another formula to use, but I can't figure it out. Without knowing the ball's initial velocity or the time of impact I'm out of ideas.