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Homework Help: Torque and equilibrium

  1. Dec 2, 2008 #1
    1. The problem statement, all variables and given/known data
    Here's the picture and I am asked to calculate the tension in the tie rope between the rod and wall

    http://img399.imageshack.us/img399/2625/masslg8.jpg [Broken]
    http://g.imageshack.us/img399/masslg8.jpg/1/ [Broken]

    2. Relevant equations

    3. The attempt at a solution

    The answer key is:

    http://img399.imageshack.us/img399/4733/answermo0.jpg [Broken]
    http://g.imageshack.us/img399/answermo0.jpg/1/ [Broken]

    I just want to know why is it using cos 60 instead of sin 60?
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Dec 3, 2008 #2
    because the angle created by the rope holding the block and the slanted thinger is 30 degrees (right triangles). So instead of putting sin 30 they just put cos 60 because sin 30 = cos 60. i hope you understand what I'm talking about
    Last edited: Dec 3, 2008
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