Halliday, Resnick & Walker — Equilibrium and Elasticity: Problem 46

46 Figure 12-47 is an overhead view of a rigid rod that turns about a vertical axle until the identical rubber stoppers A and B are forced against rigid walls at distances \(r_A = 5.0\text{ cm}\) and \(r_B = 2.0\text{ cm}\) from the axle. Initially the stoppers touch the walls without being compressed. Then force \(\vec{F}\) of magnitude \(150\text{ N}\) is applied perpendicular to the rod at a distance \(R = 5.0\text{ cm}\) from the axle. Find the magnitude of the force compressing (a) stopper A and (b) stopper B.