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Force, the things you forget.

  1. Aug 4, 2008 #1
    So, I have recently run across a real life application of things I haven't used in 10 years.

    A 170lb man is hanging from a 100 foot rope off the edge of a vertical cliff. He is pushing himself out from the rock with a 10 foot pole. The angle of the rope from the cliff is 5.74 degrees. How much force / or weight is on the pole?

    How would i figure this out? If some one could tell me, using very small words, and pretending I didn't take advanced calculus and physics.....

    I really would like to understand this again.

    Thank You.:blushing:
     
  2. jcsd
  3. Aug 4, 2008 #2
    The magnitude of the force exerted by the rope we denote by F. The upward component of this force is F * sin(84.26), which is equal to 170lb since it must balance the man's weight. So F = 170/sin(84.26). But the horizontal component, which the pole must balance, is F*cos(84.26), or 170*cot(84.26), which is about equal to seventeen pounds.
     
  4. Aug 4, 2008 #3
    Its a simple statics problem. Just sum the forces in the X and Y dimensions and solve for the unknowns, simple algebra no calc needed. Look up method of joints or methods of segments for more details.
     
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