What is the minimum normal force he must exert?

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To determine the minimum normal force a 50.0 kg climber must exert in a vertical chimney, the net force must equal zero since the climber is stationary. The climber's weight, calculated as mass times gravity, is 490 N. The static friction forces from the climber's shoes and back, influenced by their respective coefficients of friction (0.90 and 0.65), must also be considered. The friction forces can be calculated using the formula Ffr = µsFN, where FN is the normal force. The discussion emphasizes the need for a detailed calculation to ensure that the friction forces adequately counterbalance the climber's weight.
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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.
 
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physicsss said:
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.

nice story, what exactly do you want?
 
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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