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Homework Help: Tension of wires holding a suspended sign in equilibrium

  1. Mar 13, 2012 #1
    1.Hey guys, I've been struggling with this one for an hour and it SHOULD NOT be this hard for me.

    A 15kg picture hangs from a hook on the wall. What is the tension in each wire if one is at a cartesian angle of 220° and one is at a cartesian angle of 320°?


    So my physics 20 teacher told me to break it into vertical and horizontal components. I solved for one of my tensions and then tried to substitute into my second equation....that's when things get scary. Please help!

    3. I tried:

    0N = -147.15N + Ft1 (sin 220°) + Ft2 (sin 320°)

    I was trying to solve for Ft1 first.
  2. jcsd
  3. Mar 13, 2012 #2


    User Avatar

    Staff: Mentor

    You should check to see what quadrants your angles are in, and so make sure that the components you're extracting via sin and cos have the signs that you're expecting.

    It's often expedient to make a sketch and use the given angles to label other angles that are more conveniently associated with the "usual" analysis steps.
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