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Homework Help: Finding the Center of Mass

  1. Jun 21, 2009 #1
    1. The problem statement, all variables and given/known data
    Find x coordinant of the the center of mass point of a uniform wire that subtends an arc of 22 degrees if the radius of the circular arc is 1m.

    2. Relevant equations
    I begin with: length = r*theta

    Therefore M = density*r*theta

    dm = density*ds = denisty*r8*d(alpha)

    x= (1/M)*[integral of r*cos(alpha)*denisty*r*d(alpha) from (theta/2) to -(theta/2)

    Thus, I get
    x = (2r/theta)*sin(theta/2)

    3. The attempt at a solution
    I keep getting an answer of 0.01735 m. However, the online homework is telling me that it is not the correct answer.

    I am not sure where in the above calculations I would have messed up. Could someone please point out where I have made an error?

    Thank you in advance.
  2. jcsd
  3. Jun 21, 2009 #2
    okay nevermind I was forgetting to convert theta to radians.
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