Chapter 11, Problem 71GP

CE Predict/Explain A disk and a hoop (bicycle wheel) of equal radius and mass each have a string wrapped around their circumferences Hanging from the strings, halfway between the disk and the hoop, is a block of mass m, as shown in Figure 11-56. The disk and the hoop are free to rotate about their centers When the block is allowed to fall does it stay on the center line, move toward the right, or move toward the left'? (b) Choose the best explanation from among the following:

Figure 11-56 Problem 71

1. I.                    The disk is harder to rotate and hence its angular acceleration is less than that of the wheel.
2. II.                 The wheel has the greater moment of inertia and unwinds more slowly than the disk.
3. III.              The system is symmetric, with equal mass and radius on either side.