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Homework Help: A Superball Colliding Inelastically with a Table

  1. Nov 14, 2009 #1
    1. The problem statement, all variables and given/known data
    As shown in the figure, a superball with mass M equal to 50 grams is dropped from a height of h1 . It collides with a table, then bounces up to a height of h2 . The duration of the collision (the time during which the superball is in contact with the table) is T=15ms . In this problem, take the positive y direction to be upward, and use g=9.8 for the magnitude of the acceleration due to gravity. Neglect air resistance.

    previously in other parts of the problem I found that the y component of the momentum, of the ball immediately before the collision was Pbefore y =-0.27 kg*m/s and that the y component of the momentum of the ball after the collision was Pafter y=0.22 kg*m/s

    I have to find the y component of the time-averaged force Favgy, in newtons, that the table exerts on the ball

    2. Relevant equations
    I'm actually having problems figuring out what equations to use is all, the equations for force that my teachers given us for force don't use time, at least not yet.

    3. The attempt at a solution
    N/A Can't figure out the formula
  2. jcsd
  3. Nov 15, 2009 #2
    Use impulse (change in momentum) formula:

    Fave = I/[tex]\Delta[/tex]t

    where I is the impulse i.e. final momentum minus initial momentum
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