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Couple of v. important problems

  1. Sep 11, 2006 #1
    there's a couple of problems that i have to give in at the end of this lunctime that i just cant work out how to approach or what formulas to use:

    1. A 70g tennis ball falls 2 meters and bounces back up to a height of 1.9 meters
    (a)How much kinetic energy does the tennis ball have?

    (b)the ball compresses 10cm for a period of 2 seconds, what is the kinetic energy of the ball during this time?

    2) a car is travelling at 75km/h up a hill. Assuming that gravity =9.8 ms-2, what is the maximum height that the car wil reach?
  2. jcsd
  3. Sep 11, 2006 #2

    Chi Meson

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    Is the ball moving at the top of the bounce?
    Is this really the question? How can a 7 cm diameter object compress 10 cm? Anyway, same analysis. Is the ball moving while it is compressed?
    By height, it means "altitude above starting position." Consider conservation of energy: KE becomes PE.
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