Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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

    Tide

    User Avatar
    Science Advisor
    Homework Helper

    Don't forget that momentum is conserved in the collision!
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook