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Center of mass

  1. May 17, 2009 #1
    1. The problem statement, all variables and given/known data
    Let D be the region in the (x, y) plane bounded by the lines y=x, y=4x and the hyperboals xy=1 and xy=9. find the center of mass of D.

    2. Relevant equations

    3. The attempt at a solution

    My thought: to use the center of mass formula? and use the change of variables?
  2. jcsd
  3. May 17, 2009 #2


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    What have you done? The problem is to find a center of mass- why should there be a "?" on "use the center of mass formula"? Of course you shold use it. I can't speak toward "use the change of variables" because you haven't said what the integral is!

    (Strictly speaking, this is NOT a "center of mass" problem at all because you have not given any density function so there is no "mass" and no "center of mass". It is a purely geometric "centroid" problem but that can be done exactly like a "center of mass" problem assuming constant density.)
  4. May 17, 2009 #3
    the problem is not given one.

    do I have to find the area of the two regions first?

    Then what do I do next?
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