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Homework Help: Disc And Center Of Mass

  1. Aug 13, 2015 #1
    Hi New member here!
    1. The problem statement, all variables and given/known data

    In the figure one-fourth part of a uniform disc of radius R is shown. The distance of the center of mass of this object from center ‘O’ is ………………………. PictureR.png

    Given: For a semi-circular disc with origin of co- ordinate system at the center of circle, the coordinate of its center of mass is (0,4R/3π ).

    (Solve this problem without using calculus)
    3. The attempt at a solution
    I tried for hours but could not find a solution without using calculus.
    Last edited: Aug 13, 2015
  2. jcsd
  3. Aug 13, 2015 #2


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    Hello Ujjawal, welcome to PF :smile: !

    A challenging exercise. Think symmetry and folding:
    The given information tells you the center of mass shifts from 0 to ##(0,{4\pi \over 3r})## when you fold a full circle in half.

    Is that enough of a hint ?
  4. Aug 14, 2015 #3
    Yes, and thank you BvU!
  5. Aug 15, 2015 #4
    This problem actually took me quite some time to figure.......thnx for the hint BvU!
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