We model the human leg as a physical pendulum with mo- ment of inertia I = 1/3 M L2 (measured from the hip). It is a good ap- proximation to say the center-of-mass of the leg is roughly at the knee, i.e. d = 1 2 L. Each step in the action of walking is a half-swing of simple harmonic motion. In the most effortless walk, the legs swing at their nat- ural frequency, and the time for one step is T /2. Walking faster or slower requires additional muscular exertion and is more tiring. (A) What is the most effortless walking speed for a person with 90-cm-long legs if the length of each step is 90 cm? Check your answer. (B) Convert the speed to miles per hour. (1.6 km = 1 mile, 1 hour = 3600 seconds) (C) Finally, find the relationship between effortless walking speed and leg length. Do you think longer legs will be faster, or shorter legs? You will find either v L1/2 or v L1/2. Show which equation is correct, and check using dimensional analysis. Problem 3 Block B is free to slide on the horizontal surface. With block C placed on