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Homework Help: Conservation of momentum problem in variable.

  1. Oct 7, 2009 #1
    1. The problem statement, all variables and given/known data
    Tarzan mass M swings from a vine from rest at height H. At the bottom of the arc he picks up Jane of mass m in a perfectly inelastic collision. They reach a vertical height h. How far vertically above h is H?

    2. Relevant equations
    Pi = Pf
    R = [tex]\Sigma[/tex]mr/[tex]\Sigma[/tex]m

    3. The attempt at a solution
    Using conservation of momentum:
    Mv1 = (M + m)v2
    Center of mass:
    (MH + (m+M)h)/(m + M)

    I feel as though these must somehow be related to find the distance, but after looking for quite some time now, no obvious correlations are coming. I would appreciate any help in getting me in the right direction. Thanks!
  2. jcsd
  3. Oct 7, 2009 #2


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    Homework Helper

    So we can find v2 in terms of v1.

    Can you find v1 in terms of H ? (think energy)

    At the bottom of the arc, Tarzan has 0 potential energy and only kinetic energy. This kinetic energy is converted into gravitational potential energy to the height h.

    Can you find a relation between h and H now?
  4. Oct 7, 2009 #3
    Yes it is now much easier, thank you so much.
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