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Homework Help: Resolving Force vector

  1. Sep 10, 2010 #1
    fag.png 1. The problem statement, all variables and given/known data
    A resultant vertical force of 1750 N is necessary to held the balloon in place. Resolve this force into components along the tether lines AB and AC, and compute the magnitde of each force.

    The angle between AB and the vertical force is 40 deg, and the angle between AC and the vertical force is 30.

    3. The attempt at a solution

    After applying parallelogram law, I was able to produce a triangle with the angles 110, 40, and 30. I applied sine law as follow:

    Fab / sin30 = 1750 / sin 110 = Fac / sin40

    However, after computing, the answers are WAY off. I'm talking ~800-900 Newtons.

    The answers in the back of the book are Fab = 186N and Fac = 239 N.

    I just dont see how those components and angles given in the question can remotely come near the 1750 N force.. Help?>
  2. jcsd
  3. Sep 10, 2010 #2
    I suggest you draw the parallellogram to scale, and develop two equations representing vertical components and horizontal components. Check your answer by measurement of the scale drawing.
  4. Sep 10, 2010 #3
    I have done so, but again I am getting entirely different answers. Perhaps someone can point me in the right director for vector allignment? I am assuming that its my arrangment of vectors that is corrupting my answer. fag-1.png
  5. Sep 11, 2010 #4
    "The answers in the back of the book are Fab = 186N and Fac = 239 N. "

    Diagram looks ok. Book answers don't.
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