Chapter 3, Problem 46P

In a motion capture study of a runner, one frame shows the subject supporting her weight on one leg, as shown in Fig. P3.46. The length of the foot

segment (from ankle to toe) is 8 in, and the length of the lower leg (from ankle to knee) is 18 in.

(a) Given the angles shown in Fig. P3.46(a), find the position of the knee if the runner’s toes touch the ground at the point $x=y=0$.

(b) Now suppose that the same leg is positioned such that the knee is located in the second quarantined oriented in the knee-down position (clockwise direction). as shown in Fig. P3.46. If the toes are located at $P\left(x,v\right)=\left(-6.25\text{ in}.,25\text{ in}.\right)$, determine the values of ${\theta }_1$ and ${\theta }_2$.