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Homework Help: Rock Climbin

  1. Nov 14, 2007 #1
    1. The problem statement, all variables and given/known data

    A mountain climber is rappelling down a vertical wall. The rope attaches to a buckle strapped to the climber's waist 15 cm to the right of his center of gravity and makes an angle of = 15° with the wall. The climber weighs 780 N.
    (a) Find the tension in the rope

    (b) Find the magnitude and direction of the contact force exerted by the wall on the climber's feet.

    Magnitude 209 N
    Direction ____ ° above the horizontal.

    2. Relevant equations

    3. The attempt at a solution

    when finding the tension of the rope, how is it possible that I found the magnatude of the feet against the wall and couldnt find the tension of the rope? Arent they part of the same equation?

    Is this like a fulcrum problem?
  2. jcsd
  3. Nov 14, 2007 #2


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    Homework Helper

    You need to find the component of the reaction at right angles to the wall.
    You have the force downward (weight) and so the magintude of the tension is just the long side of the force triangle - like the length of the rope in the diagram.
  4. Nov 14, 2007 #3
    Thats not the right answer though I have already tried it.
  5. Nov 14, 2007 #4
    "The moment of a force about a point is equal to the force times the perpendicular distance from the line of action of the force to the point"

    Using this rule and what you have been told, you need to get the tension in terms of a 'perpendicular distance'.
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