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Homework Help: Tennis ball rebounding off the wall question

  1. Sep 26, 2009 #1
    1. The problem statement, all variables and given/known data
    A tennis ball has a mass of 0.057 kg. A professional tennis player hits the ball hard enough to give it a speed of 50 m/s (about 112 miles per hour.) The ball moves toward the left, hits a wall and bounces straight back to the right with almost the same speed (50 m/s). As indicated in the diagram below, high-speed photography shows that the ball is crushed about 2 cm at the instant when its speed is momentarily zero, before rebounding.

    Assume that the large force the ball exerts on the wall is approximately constant during contact.

    2. Relevant equations
    What is the average speed of the ball during the period from first contact with the wall to the moment the ball's speed is momentarily zero?

    How much time elapses between first contact with the wall, and coming to a stop? (ans in seconds)

    What is the magnitude of the average force exerted by the wall on the ball during contact?

    In contrast, what is the magnitude of the gravitational force of the Earth on the ball? (ans in N)

    3. The attempt at a solution
  2. jcsd
  3. Sep 27, 2009 #2


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    What equations do you think are relevant to this problem?

    This problem describes a collision between two objects. What is quantities come into play when you have a collision?

    How do you find average speed? Does the ball accelerate after it touches the wall? If so, how can you find the average acceleration?

    What are your thoughts on all of the above?
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