The thrust bearing is supported by contact of the collar C with a fixed plate. The area of...

The thrust bearing is supported by contact of the collar C with a fixed plate. The area of contact is an annulus with an inside diameter D1 = 40 mm and an outside diameter D2 = 120 mm. The coefficient of kinetic friction between the collar and the plate is μk = 0.3. The force F = 400 N. What couple M is required to rotate the shaft at a constant rate?

(See Example 9.8.)