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Homework Help: What is the minimum normal force he must exert?

  1. Sep 29, 2004 #1
    The 50.0 kg climber is supported in the "chimney" by the friction forces exerted on his shoes and back. The static coefficients of friction between his shoes and the wall, and between his back and the wall, are 0.90 and 0.65, respectively. What is the minimum normal force he must exert? Assume the walls are vertical and that the static friction forces are both at their maximum, Ffr = µsFN.
  2. jcsd
  3. Oct 2, 2004 #2
    nice story, what exactly do you want?
  4. Feb 26, 2005 #3
    So I know the net force must equal zero because the climber isn't moving.
    I'm assuming the Ff can be determined by multiplying the mass*gravity*friction-coefficient.
    But it seems that if Fnet=0, then the minimum Ff should just be equal to the climber's weight. (ie. Fg + Ff(1) + Ff(2) = 0 )

    Hopefully I can get some help on this because it can't be that simple.
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