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Homework Help: Physics hw help please

  1. Nov 18, 2008 #1
    A catcher catches a 145g baseball traveling horizontally at 34.0 m/s

    1. How large an impulse does the ball give to the catcher?
    2. If it takes the ball 23.0ms to stop once it is in contact with the catcher's glove, what average force did the ball exert on the catcher?

    is this right...

    1. .145 kg x 34.0 m/s = –4.93 kg m/s (the minus sign indicates the force acts in the opposite direction of the baseball's velocity).

    2. The impulse I = F x t and F = I / t = –4.93 kg m/s / 0.0230 s = 214 kg m/s^2 = 214 N
  2. jcsd
  3. Nov 18, 2008 #2


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    Aren't 1) and 2) asking about what the ball delivers? Won't the force of the ball delivers be positive if V is in the positive direction?
  4. Nov 19, 2008 #3
    Momentum is mass x velocity, while the force = rate of change of momentum; i.e. d(mv)/dt.
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