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Homework Help: Impulse: Clay ball that sticks vs. Rubber ball that bounces?

  1. Feb 28, 2010 #1
    1. The problem statement, all variables and given/known data

    A 10 g rubber ball and a 10 g clay ball are thrown at a
    wall with equal speeds. The rubber ball bounces, the
    clay ball sticks. Which ball exerts a larger impulse on
    the wall?

    2. Relevant equations

    J (impulse) = Favg*dt

    3. The attempt at a solution

    I think that the rubber ball would exert more of an impulse because it's dt would be larger. Since it has to hit the ball and bounce of it, as opposed to the clay, which hits the wall and stops.

  2. jcsd
  3. Feb 28, 2010 #2


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    Homework Helper

    Impulse is either F*Δt or m*Δv.
    The first expression is difficult to use because you don't actually know the force and duration of the collisions with the wall. Use the second expression. The difference is in the Δv.
  4. Mar 2, 2010 #3
    Thought I replied to this.

    Okay, so with the clay ball, the change in v is from x to 0, so it's -x. The rubber ball bounces though...and though it may leave the wall with a different speed, it's velocity has changed more than the clay ball's since it changed direction (x to -x...so -2x roughly). Therefore the rubber ball is exerts more impulse on the wall?
  5. Mar 2, 2010 #4
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