1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Static Equilibrium Climber Problem

  1. Apr 5, 2009 #1
    1. The problem statement, all variables and given/known data

    A climber with a weight of 510 N is held by a belay rope connected to her climbing harness and belay device; the force of the rope on her has a line of action through her center of mass.The indicated angles are θ = 41˚ and φ = 26˚. If her feet are on the verge of sliding on the vertical wall, what is the coefficient of static friction between her climbing shoes and the wall?

    2. Relevant equations

    Sum of all forces = 0
    Sum of all torques = 0

    3. The attempt at a solution


    FN - Normal force from the wall
    T - Tension from rope
    Fs - Static friction

    What am I doing wrong?
  2. jcsd
  3. Apr 5, 2009 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    One has

    FN - Normal force from the wall
    Fs - Static friction

    but Fs = μFN and must act vertically, opposite the weight of the climber.

    T must be resolved into x (horizontal) and y (vertical) components,

    and one must consider the torques, which must equal zero.

    The climber's moment is the length of rope, but the moment opposing is the distance from from the rope at the wall to the feet.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook