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Homework Help: Finding center of mass of a picture

  1. Nov 13, 2005 #1
    hey everyone, im stumped as to finding the x and y coords of the center of mass of this picture. it is supposed to be a uniform sheet of steel in increments of 6. please help, i have an exam tomorrow.

  2. jcsd
  3. Nov 13, 2005 #2
    What exactly is the centre of mass?

    Once you have the answer, you can "decompose" it into two components, x and y. So you'd basilcally find the centre line along x, then along y, and your centre point would be the intersection of the two.
  4. Nov 13, 2005 #3
    i'm still stumped heh
  5. Nov 13, 2005 #4
    Find the CoM in each direction seperately. Meaning stack all the blocks so that you only have one direction to deal with at a time. For example, imagine a figure with 3m on the left column, 2m in the middle column, and 1m on the right column (where m is the mass of one block). then find the center of mass of those 3 blocks, this corresponds to the CoM in the x direction. Do something similar for the y direction.
  6. Nov 13, 2005 #5
    The centre of mass is a point around which all the mass is symmetrically arranged.

    Take the x direction for example. For what value of x would the mass be symmetrically distributed, i.e. you have the same mass to the right and to the left of your x value?

    Note that if you balance your plate on a knife edge placed at that x, the plate would be in equilibrium.
  7. Nov 13, 2005 #6
    i got it, thanks. answer is (7,8) btw
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