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Homework Help: Tension - Physics

  1. Jul 20, 2009 #1
    1. The problem statement, all variables and given/known data
    Pulling the string on a bow back with a force of 30.0lb , an archer prepares to shoot an arrow.

    If the archer pulls in the center of the string, and the angle between the two halves is 126 degrees, what is the tension in the string?

    2. The attempt at a solution

    cos (126/2) = 30/T

    This answer is wrong. I don't know where I messed up. I even got 66 and 60 once during trying to solve this. All of them were wrong.

    Can anyone please help me out?
  2. jcsd
  3. Jul 20, 2009 #2


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    Homework Helper

    If you draw the vectors for the two tensions, you should get two vector components in the direction opposite to the 30lb pulling force.
  4. Jul 20, 2009 #3
    I tried something like this
    2Tcos(126/2) =30
    T = 33.07
    is it close enough?

    Thanks a lot!
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