The speed of the brake drum shown is controlled by a belt attached Problems 457 to the con...

The speed of the brake drum shown is controlled by a belt attached Problems 457 to the control bar AD. A force P of magnitude 25 lb is applied to the control bar at A. Determine the magnitude of the couple being applied to the drum, knowing that the coefficient of kinetic friction between the belt and the drum is 0.25, that a = 4 in., and that the drum is rotating at a constant speed (a) counterclockwise, (b) clockwise.

Fig.P8.113