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Homework Help: Energy lost during collision

  1. May 22, 2009 #1
    1. The problem statement, all variables and given/known data

    A 40.8 g ball of clay hits and sticks to a 3.41 kg block sitting at rest on a frictionless surface. What is the speed of the block after the collision if the initial speed of the ball of clay is 5.04 m/s?
    b)What percentage of the system's initial energy is lost?

    2. Relevant equations

    pinitial=pfinal, E=0.5mv2

    3. The attempt at a solution

    for the first part i figured out the speed final which is 0.0596 m/s
    for the second part for each i figured the initial energy and then the final energy using the energy equation for both objects involved. after this part i am stuck to figure out the energy lost i came up with this equation 100-(Einitial-Efinal/Efinal) x100.. i used it and am not getting the right answer..pls. help
  2. jcsd
  3. May 22, 2009 #2


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    Homework Helper

    Divide by initial energy, not final energy (that's what it means by "percentage of the initial energy").
  4. May 22, 2009 #3
    thanks :)
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