Chapter 12, Problem 3Q

Figure 12-17 shows four overhead views of rotating uniform disks that are sliding across a frictionless floor. Three forces, of magnitude F, 2F, or 3F act on each disk, either at the rim, at the center, or halfway between rim and center. The force vectors rotate along with the disks, and, in the “snap shots” of Fig. 12-17, point left or right. Which disks are in equilibrium?

Figure 12-17 Question 3.