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Homework Help: Mountain climber - center of gravity, tension, angles

  1. Oct 24, 2007 #1
    1. The problem statement, all variables and given/known data

    A mountain climber is rappelling down a vertical wall (the figure below ). The rope attaches to a buckle strapped to the climber's waist 15 cm to the right of his center of gravity. If the climber weighs 770 N, find (a) the tension in the rope and (b) the magnitude and direction of the contact force exerted by the wall on the climber's feet.


    # (a) 750 N; (b) 310 N at 22° above the horizontal
    # (a) 730 N; (b) 330 N at 19° above the horizontal
    # (a) 730 N; (b) 300 N at 16° above the horizontal
    # (a) 750 N; (b) 330 N at 19° above the horizontal
    # (a) 770 N; (b) 300 N at 16° above the horizontal

    2. Relevant equations

    basic equations...
    F = ma
    sin = o/h
    cos = a/h
    tan = o/a

    3. The attempt at a solution

    i don't really know where to start.
    i have examples of the rope being attached to the climber's CoG, so i tried to work the problem like one of those and came out with a tension of 744 N.

    any help would be GREATLY appreciated!
  2. jcsd
  3. Oct 24, 2007 #2

    Doc Al

    User Avatar

    Staff: Mentor

    This is an equilibrium problem, so apply the conditions for equilibrium: The forces (in any direction) must add to zero and the torques (about any point) must add to zero.
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