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Homework Help: Equilibrium question with attached diagram

  1. Jan 17, 2010 #1
    1. The problem statement, all variables and given/known data

    In the attached Diagram, the mass of 2kg is held in a stable equilibrium by two strings acting horizontally and 60 degrees to the horizontal, respectively. Calculate the tension (force) T1 and T2 required to keep the 2kg mass in equilibrium.

    3. The attempt at a solution

    Resolve forces horizontally
    a) T1 Sin 60 = T2 cos 0 = 0.86

    Resolve forces vertically
    b) (T1 Sin 30 + T2 Sin 90) x 9.81 = 14.715

    Substitute a into b

    That's as far as I have got, and I don't think what I have done is right!

    Any help is appreciated, thanks in advance.

    Attached Files:

  2. jcsd
  3. Jan 17, 2010 #2


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    You've fot T1 and T2, and your trig functions, reversed. And don't forget Newton 1. The horiz component of a force P is Pcostheta, where theta is measured from the horizontal. The vert componnet of a force P would be Psintheta. Solving in the vert direction first for the equilibrium condition sum of forces vertically = 0 gives you T1 right off the bat.
  4. Jan 17, 2010 #3
    Thanks for the reply, much appreciated only if you (or anybody) could go into slightly more detail on how to solve?

    I'm not quite sure on what you have explained!

    Thanks again
  5. Jan 17, 2010 #4


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    well, it's T2cos60 =T1cos0 , or .5T2 =T1, right?
    it's T1sin60 +T2sin 0 = what?? (upward forces must equal downward forces).
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