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Momentum in a jump ball

  1. Mar 4, 2008 #1
    A basketball is tossed up into the air, falls freely, and bounces from the wooden floor. From the moment after the player releases it until the ball reaches the top of its bounce, what is the smallest system for which momentum is conserved?

    Here are some choices given...

    - momentum is not conserved
    - the ball plus Earth
    - the ball
    - the ball plus floor
    - the ball plus player

    I'm pretty sure that its not the first one, since there has to be a system in this situation where momentum is conserved. I know that the system between the Earth and the floor are really large, so it cannot be those. I am confused about the last two options: the ball alone and the ball plus player. I'm really leaning on the ball plus player because I know th initial momentum for both were zero, but I'm not sure about which part of the situation I'm going to consider for the final momentum. Any words of advice would be appreciated.


  2. jcsd
  3. Mar 4, 2008 #2
    Please...can anyone help me?
  4. Mar 4, 2008 #3

    Doc Al

    User Avatar

    Staff: Mentor

    Momentum is conserved as long as no external forces act. Analyze each of those candidate systems and see if there are any external forces acting.
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