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Impact Force Problem

  1. Feb 27, 2007 #1
    When dropping a metal ball onto a foam mat what is the formula for the impact speed. I know the impact speed, rebound speed, the mass of the ball and time of the ball on the mat.

    I know:

    F = m[delta]v


    F = mg , where g= -9.8 N/kg

    But what is the impact force?

    Is it F = m[delta]v + mg ?
  2. jcsd
  3. Feb 27, 2007 #2

    [tex] F = \frac{d\rho}{dt} [/tex]


    (Does my LaTeX work?)
  4. Feb 27, 2007 #3
    ok, but still I don't understand whether the weight force affects the value of the impact force.

    The ball is being dropped vertically, so do we add the weight force to dp/dt?
  5. Feb 27, 2007 #4


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    When you calculate the momentum change over time, you are calculating the NET force acting on the object, per Newton's 2nd law. The net force is a combination of the gravity force downward and the normal force upward. So, what does that tell you about the 'impact' (normal) force?
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