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Physics: Ladder Problem

  • Thread starter Icefire_16
  • Start date
  • #1

Homework Statement:

A 400N woman climbs a 100N, 10m ladder inclined at an angle of Θ = 60°. When she is 3m away from the wall, how much friction is needed at point A to keep the ladder from slipping. (Assume theres no friction between wall and ladder.) (Answer 342N)

Homework Equations:

Fground = mg + mdg
Fn = Ffriction
Torque = Fn(d3) -mg(d2) - m2g(d1)
I set up all my summations and ended with Fnormal = ((mg1d1) + (m2gd2)) / d3. The values I put in were ((400 x 2) + (100 x 5cos60)) / 10sin60.
I got 121.243 N as my answer but that is incorrect. What did I do wrong?
IMG_0974.JPG
 

Answers and Replies

  • #2
haruspex
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Please define all your variables (d, d1, d2, d3, m, m2, Fn) and specify your choice of axis for torque summation.
(Fn sounds like it should be normal force, but you wrote Fn=Ffriction.)
 

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