1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Need to find center of mass of a rod

  1. Apr 25, 2008 #1
    [SOLVED] Need to find center of mass of a rod

    1. The problem statement, all variables and given/known data
    Where is the center of mass of a uniform, L-shaped iron rod of sides X = 0.8 m and Y = 0.5 m, respectively? Take the corner to be at (x,y) = (0,0), with the X and Y sides along those axes, respectively. (Assume that the rod is so narrow that the dimensions of the outer bend are the same as those of the inner bend of the L.)



    2. Relevant equations



    3. The attempt at a solution

    i dont know if this involves integration, but it doesnt look like it, i think that xcm = 1/length total * ( (.8)(0) +(.8)(.8), but it does not work out
     
  2. jcsd
  3. Apr 25, 2008 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Start by finding the center of mass of each side separately. Then use that to find the center of mass of the complete object.
     
  4. Apr 25, 2008 #3
    how do i know the center of mass if im not given the mass?

    i broke it into 2 parts

    (ycm)(Mt) = (m1)(Y1) +(m2)(Y2) Y1 = 0 Y2 = .5, but the unknowns are mass

    (xcm)(Mt) = (m1)(X1) + (m2)(X2) X1 = 0 X2 = .8
     
  5. Apr 25, 2008 #4

    Doc Al

    User Avatar

    Staff: Mentor

    The mass of each side is proportional to its length. That's all you need.

    Careful here: X1, Y1 should be the center of one side; X2, Y2, the center of the other.
     
  6. Apr 26, 2008 #5
    but should'nt X1 and Y1 be treated as the reference line?
     
  7. Apr 26, 2008 #6

    Doc Al

    User Avatar

    Staff: Mentor

    Not sure what you mean. X & Y are the coordinates of the centers of each side. (Try drawing yourself a diagram.)
     
    Last edited: Apr 26, 2008
  8. Apr 26, 2008 #7
    Break it and sum. Everything is linear when talking about center of mass
     
  9. Apr 26, 2008 #8
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Need to find center of mass of a rod
Loading...