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Homework Help: Kinetic energy: what percentage has been lost?

  1. Nov 12, 2012 #1
    1. The problem statement, all variables and given/known data
    So theres a particle of mass 4u that strikes another particle of mass 196u. The collision is elastic. What percentage of its original kinetic energy has the moving particle lost?

    2. Relevant equations
    m1v1o + m2v2o = m1vf + m2v2f
    K1o + K2o = K1f + K2f

    3. The attempt at a solution
    so because its elastic, the kinetic energy total will not change, thus the Kt= Kft.
    V2o will be zero, because its not moving. It is possible to set the two equations, one for momentum and the other for Kinetic Energies, equal to each other and cancel out v2f. This helps reduce the problem to
    24Vo^2 + VoVf = 25Vf^2
    how would having this equation help me find the percentages? Am I on the right track at all?
  2. jcsd
  3. Nov 12, 2012 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    If the collision is head-on, then yes, the problem can be solved.

    What is K1F/K10 ?
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