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Homework Help: Vectors and forces

  1. Dec 30, 2009 #1
    1. The problem statement, all variables and given/known data

    A sign weighs 150n and is suspended on 2 wires between 2 walls, 1 at 50 degrees to the wall and the other at 40 deg to the other wall. What is the tension in each wire?

    2. Relevant equations

    3. The attempt at a solution

    For the 1st wire F=150/cos50
    2nd wire F=150/cos40
    Is this likely to be correct I can't find any simular examples to help me out.
  2. jcsd
  3. Dec 30, 2009 #2


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    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi P.townsville! Welcome to PF! :smile:

    (have a degree: º :wink:)
    Nooo :redface:

    you're saying F1cos50º = 150, F2cos40º = 150.

    But if you're taking vertical components, that'll be F1cos50º + F2cos40º = 150, won't it?

    Hint: you need one equation for both vertical components, and another equation for both horizontal components, and then a bit of algebra and trig. :smile:

    (Alternatively, find a direction in which you can ignore one of the tension forces :wink:)
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