(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Prof. Holland, in his younger days, (when he had a mass of 55kg) is in a lie-back climb along a fissure, with hands pulling on one side of the fissure and feet pressed against the opposite side. The fissure has width w = 0.25m, and the center of mass of the climber is a horizontal distance d = 0.43m from the fissure. The coefficient of static friction between hands and rock, μhands, is 0.42, and between boots and rock, μboots is 1.25.

What is the least horizontal pull by the hands and push by the feet that will keep him stable?

2. Relevant equations

Weight: 0 = (Ushands*Fa + Usboots*Fb) -539N

Fb=force by boots

Fa=force by hands

Torque: 0 = Fa*Distance from CM + Fb*Distance from CM

3. The attempt at a solution

So I tried setting up an equation for the forces made by the hands and feet which was the "Weight" equation above. Then I created the "Torque" equation. I knew since the climber(Professor Holland) was in static equilibrium that the both of them had to equal zero. I solved for both of the forces and keep coming up with A=786.6369N and B=166.89N and A+B(what they're looking for)=953.5269N.

I have to submit it online and it says that the answer is not correct. What am I doing wrong? I don't understand this problem!!!!AHHHHH!

Thanks,

Matt

oh yeah forgot, thanks in advance for the help....it's much needed.

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# Homework Help: Another torque/statics problem

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