The pulley of 50-mm radius is mounted on a shaft of 10-mm radius. The shaft is supported b...

The pulley of 50-mm radius is mounted on a shaft of 10-mm radius. The shaft is supported by two journal bearings. The mass of the block A is 8 kg. Neglect the weights of the pulley and shaft. If a force T = 84 N is necessary to raise block A at a constant rate, what is the coefficient of kinetic friction between the shaft and the bearings?