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Homework Help: Center of mass?

  1. Nov 13, 2009 #1
    1. The problem statement, all variables and given/known data

    Consider the following mass distribution where the xy coordinates are given in meters: 5 kg at (0.0, 0.0) m, 3 kg at (0.0, 4.0) m, and 4 kg at (3.0, 0.0) m. Where should a fourth object of 8 kg be placed so the center of gravity of the four-object arrangement will be at (0.0, 0.0) m?

    2. Relevant equations

    Just guessing,

    Xc of m = [tex]\Sigma mi*xi\Sigma mi

    3. The attempt at a solution

    I am guessing that it should be in the bottom left of the xy coordinate. Buy I don't know how to start the problem.
  2. jcsd
  3. Nov 13, 2009 #2


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    Homework Helper

    The equation you have is right: the sum of the mi*xi for each individual mass is equal to the x-coordinate of the center of mass. The same applies to the y-coordinate of the mass center: it's equal to sigma mi*yi.
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