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Homework Help: Minimizing a vector in a triangle

  1. Jul 27, 2010 #1
    1. The problem statement, all variables and given/known data

    A truck is to be towed using two ropes. If the resultant force is to be 950N, directed along the positive x axis, determine the magnitudes of forces F1 and F2 acting on each rope and the angle at which rope two pulls to ensure that the magnitude of F2 is a minimum. F1 acts at 20 degrees from the x axis.

    3. The attempt at a solution

    I assumed that to minimize the work required by rope two, it would be -90degrees angle (so it is only required to pull the truck back in line). However, the book says -70degrees?
  2. jcsd
  3. Jul 27, 2010 #2


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    Hi Shaybay92! :smile:

    (have a degree: º :wink:)
    Sorry, no idea what you mean. :confused:

    Anyway, just draw a vector triangle …

    you know the direction and length of one side, and you know the direction of the second side …

    what is the shortest the third side can be? :smile:
  4. Jul 27, 2010 #3
    I'm assuming based on the wording that there's a diagram that goes with this? It's kinda hard to solve a geometry problem if there's supposed to be a picture with it.
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