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Homework Help: Multiple choice ? on center of mass

  1. Apr 9, 2005 #1
    Two balls of masses m1 and m2 are moving along x-axis w/ velocities, v1>v2>0. After transforming from the lab frame to the center-of-mass frame, what are the velocities of m1, v1com, and mass m2, v2com? Vcom is the center of mass velocity for the system of both balls. The choices are:

    1.v1com=+v1-Vcom, v2com=+v2+Vcom
    2.v1com=+v1-Vcom, v2com=+v2-Vcom
    3.v1com=+v1+Vcom, v2com=+v2+Vcom
    4.v1com=+Vcom, v2com=+Vcom
    5.v1com=+Vcom-v1, v2com=+Vcom+v2
    6.v1com=+v1+Vcom, v2com=+v2-Vcom
    7.v1com=+Vcom+v1, v2com=+Vcom-v2
    7.v1com=+Vcom-v1, v2com=+Vcom-v2
    9.v1com=+v2, v2com=+v1
  2. jcsd
  3. Apr 9, 2005 #2


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    Science Advisor

    Choice #2
    (When transforming to COM Frame, the new apparent entity velocities will be relative to Vcom, that is, Vcom will appear subtracted from v1 & v2.)

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