The sport of gymnastics requires both impressive physical strength and extensive training for balance. The iron cross is an exercise performed on two suspended rings, which the gymnast grips with his hands. Suppose that a male gymnast wishes to execute an iron cross during a gymnastics session (Figure 6.39/p.
428). The total mass of the gymnast is 125lbm. Each ring supports half of the gymnast's weight. Assume that the weight of one of his arms is 5% of this total body weight. The distance from his shoulder joint to where his hand holds the ring is 56cm. The distance from his hand to the center of mass of his arm is 38cm. The horizontal distance from his shoulder to the middle of his chest, directly above the center of
mass of his body, is 22cm. If the gymnast is still, how much force and torque are at one of his shoulder joints?