The 75 kg climber in Figure is supported in the chimney by the friction forces exerted on

The 75 €“kg climber in Figure is supported in the €œchimney€ 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 0.80 and 0.60, respectively. What is the minimum normal force he must exert? Assume the walls are vertical and that friction forces are both at a maximum, Ignore his grip on the rope.