Chapter 12, Problem 42AP

When a person stands on tiptoe on one foot (a strenuous position), the position of the foot is as shown in Figure P12.32a. The total gravitational force ${\stackrel{\to }{F}}_g$ on the body is supported by the normal force $\stackrel{\to }{n}$ exerted by the floor on the toes of one foot. A mechanical model of the situation is shown in Figure P12.32b, where $\stackrel{\to }{T}$ is the force exerted on the foot by the Achilles tendon and $\stackrel{\to }{R}$ is the force exerted on the foot by the tibia. Find the values of T, R, and θ when F_g = 700 N.

Figure P12.32