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Homework Help: Kinetic energy help

  1. Oct 9, 2004 #1
    Can someone help me with this:

    For a completely inelastic collision, the fractional change in kinetic energy can be found as a function of the masses of the projectile and target carts only. Show that the fractional change in kinetic energy is given by:

    [KE(final) - KE(initial)] / KE(initial) = -M / (m + M)

    I know that KE = 1/2 mvsquared
    but I can't seem to cancel v out to get -M / (m + M)
  2. jcsd
  3. Oct 9, 2004 #2


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    Don't forget that momentum is conserved in the collision!
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