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Homework Help: Mass of a rod

  1. Apr 8, 2010 #1
    1. The problem statement, all variables and given/known data
    A long thin rod lies along the x-axis from the origin to x=L, with L= 0.750 m. The mass per unit length, l (in kg/m) varies according to the equation l = l0 (1+1.110x2). The value of l0 is 0.500 kg/m and x is in meters.

    2. Relevant equations
    stated in equation

    3. The attempt at a solution
    I am lost on this question, i tried plugging the given numbers into the above equation, but my answer is not right(and tbh that seemed entirely to easy)

    so i know .50*(1+1.110*.750^2) is not right, but other then that i am stuck, any help is greatly appreciated
  2. jcsd
  3. Apr 8, 2010 #2


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    Homework Helper

    You need to integrate over the entire length of the rod.
  4. Apr 8, 2010 #3
    alright i solved for the mass and got .453 kg, which is correct.

    Now i need to figure out

    Calculate the x-coordinate of the center of mass of the rod.

    I tried integrating x*m then dividing by m, but that didnt work
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