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Homework Help: Constant force exerted on the ball by the wall?

  1. Feb 10, 2004 #1
    a 2.5 kg ball strikes a wall with a velocity of 8.5 m/s to the left. The ball bounces off with a velocity of 7.5 m/s to the right. If the ball is in contact with the wall for .25s, what is the constant force exerted on the ball by the wall?
  2. jcsd
  3. Feb 10, 2004 #2


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  4. Feb 10, 2004 #3


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    Momentum to the left, before the collision, is (- 8.5m/s)(2.5 kg) (negative because it is to the left). Momentum to the right, after the collision is (7.5 m/s)(2.5kg). Change in momentum is the difference between those: (7.5 m/s)(2.5kg)+(8.5m/s)(2.5 kg).
    Since that took place in 0.25 s, the average rate of change of momentum is that divided by 0.25 s. Force IS rate of change of momentum.
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