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Homework Help: Center of mass to find support reactions at pins for a homogeneous flat plate

  1. Aug 28, 2011 #1
    1. The problem statement, all variables and given/known data
    The mass of the homogeneous flat plate is 50 kg. Determine the reactions at the supports A and B. I've attached the diagram.

    3. The attempt at a solution
    I know I will need to find the center of mass. I don't remember exactly how to do it, but I found the centroid location first by using composite areas and the formula xbar=∑(x~)A/∑A and similar for y.
    I found the centroid location to be at (0.566,0.183) m.

    I have two questions.
    If I find the center of mass, do I then just treat the mass as a concentrated load at that point horizontally and find the reactions using the moment about A or B and the sum of the forces in the y?
    Can someone point me in the right direction for finding the center of mass from here?

    Thank you!

    Attached Files:

    Last edited: Aug 28, 2011
  2. jcsd
  3. Aug 28, 2011 #2
    I think I figured it out. I didn't need to do anything beyond finding the centroid location to find the support reactions. I got an answer of By= 198 N and Ay = 292 N
  4. Sep 1, 2011 #3

    rude man

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    Homework Helper
    Gold Member

    You got it. But they made finding the centroid a bit of an exercise, eh?
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