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Homework Help: Center of Mass

  1. Sep 18, 2010 #1
    1. The problem statement, all variables and given/known data

    Prove that the magnitude R of the position vector for the centre of mass from an arbitrary origin is given by the equation

    M2R2 = M[tex]\sum[/tex]miri2 - (1/2)[tex]\sum[/tex]mimjrij2

    2. Relevant equations

    F = MR''

    F = p'

    p = [tex]\sum[/tex]mjrj'

    3. The attempt at a solution

    I'm not quite sure where to start with this, but this is what I've tried so far:

    F = MR''

    R'' = [tex]\frac{F}{M}[/tex] = [tex]\frac{p'}{M}[/tex] = [tex]\frac{([tex]\sum[/tex]mjrj')'/M

    And that's about where I think I go wrong. Am I on the right path, or am I waaayyy off?
  2. jcsd
  3. Sep 18, 2010 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    We cannot see what you have done because your LateX code failed. Try re-posting and someone might be able to help you.
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