A Physics, Frictional Force Problem?

Question

Please help me solve this problem
If you can please write step by step
The Problem is:
A 70 kg climber is supported in a chimney by the friction forces exerted on his shoes and back, which are in contact with the vertical walls. The coefficients of static friction between his shoes and the wall and his back and the wall are 0.8 and 0.6 respectively. What is the minimum normal force he must exert? The normal force he exerts is the same for both walls?

Thanks

Note that the laws to solve is here
Ff = uFn
Fs=usFn

Answer 1

This also depends on the mass distribution between the two walls. In reality the mass will be concentrated more on the side of his back. Since the distribution is not given, I'll assume it is equally distributed between the two walls. Also, the angle of the climber's legs will have to be assumed to be perfectly horizontal, also unlikely. Given that, the minimal frictional force must be equal to the 1/2 the climber's weight, and, since the wall is the lower coefficient:

.5*70*9.8=N*0.6
N=572 N

j

Answer 2

Fk = zero.two m = five kg d = 10 m g = nine.eight m/s squared (or in my case, my trainer has us circular to ten m/s squared Ff = Fk x m x g Ff = zero.two x five kg x 10 m/s squared = 10 W = F x d W = 10 (reply from above) x 10 m = one hundred J however considering the fact that the frictional drive acts in opposition to the path the sled is journeying, the reply is -one hundred J