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Homework Help: Having trouble finding the center of mass for multiple objects

  1. Jan 12, 2010 #1
    1. The problem statement, all variables and given/known data

    Find the x-coordinate of the center of mass of the composite object shown in the figure. The sphere, cylinder, and rectangular solid all have a uniform composition. Their masses and dimensions are: sphere: 200 g, diameter = 10 cm; cylinder: 450 g, length = 11 cm, radius = 5.0 cm; rectangular solid: m = 220 g, length in x-direction = 16 cm, height = 10 cm, depth = 12 cm.

    2. Relevant equations

    using the formula: x1m1+x2m2+x3m3 / Total mass of objects

    3. The attempt at a solution

    200(10) + 11(450) + 16(220) / 870 = 12.0346

    what am I missing/doing wrong?
  2. jcsd
  3. Jan 12, 2010 #2


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    Homework Helper

    In the formula

    [tex]M \bar{x}=m_1x_1+m_2x_2+m_3x_3[/tex]

    x1,x2 and x3 are the centroids of the masses m1, m2 and m3 respectively.

    I don't think the centroid of a sphere is at the end of its diameter.
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