Chapter 5.1, Problem 13E

Leg traction. The accompanying figure shows how a legmay be stretched by a pulley line for therapeutic purposes. We denote by ${\stackrel{\to }{F}}_1$ the vertical force of the weight.The string of the pulley line has the same tension everywhere; hence, the forces ${\stackrel{\to }{F}}_2$ and ${\stackrel{\to }{F}}_3$ have the samemagnitude as ${\stackrel{\to }{F}}_1$ . Assume that the magnitude of eachforce is 10 pounds. Find the angle $\theta$ so that the magnitude of the force exerted on the leg is 16 pounds. Roundyour answer to the nearest degree. (Adapted from E.Batschelet, introduction 10 Mathematics for Life Scientists, Springer. 1979.)