The homogeneous horizontal bar AB weighs 20 lb. The homogeneous disk weighs 30 lb. The coe...

The homogeneous horizontal bar AB weighs 20 lb. The homogeneous disk weighs 30 lb. The coefficient of kinetic friction between the disk and the sloping surface is μk = 0.24. What is the magnitude of the couple that would need to be applied to the disk to cause it to rotate at a constant rate in the counterclockwise direction?