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Homework Help: Tension vectors

  1. Jan 8, 2010 #1
    1. The problem statement, all variables and given/known data
    My books doesn't seem to give a good explanation of tension vectors. I was hoping someone on here could explain them better.
    I put the picture from the book up.

    The two questions with pictures are the one's I'm having trouble with.
    In case you can't read them:
    The one with the red box says,
    A 112.1-kg sign is hung from two strings as shown below. What is the tension in each string?
    [tex]\theta[/tex] = 35.0 degrees on the string going to the right and [tex]\theta[/tex] = 50.0 degrees

    The second question with the fish says,
    A fisherman is deisplaying his prize catch by hanging it as illustrated below. The horizontal string in the hanging apparatus is weak and will only be able to stand a tension of 13.0 pounds before it breaks. What is the maximum weight for a fish to hang on this system?

    T= 13.0 lbs max [tex]\theta[/tex] = 40.0 degrees

    I get think I get the concept it's the math and finding what information I already know that's giving me the trouble.

    Thanks for any help.
  2. jcsd
  3. Jan 8, 2010 #2


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    Science Advisor
    Homework Helper

    Hi Gamegoofs2! :smile:

    (have a theta: θ :wink:)
    The great thing about tension is that you always know the direction, it has to be along the string.

    The general trick is to call the tensions T1 and T2, find two equations, and solve.

    The two equations are usually by taking components of force in the x and y directions (or any two other convenient directions). Sometimes you take moments about a convenient point, instead of one of the directions.

    If you're still worried, show us how you'd deal with one or both of those problems. :smile:
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