Disk b weighs 50 lb and has a centroidal radius of gyration of 8 in. the power unit c consists of a motor m and a disk a, which is driven at a constant angular speed of 1600 rev/min. the coefficients of static and kinetic friction between the two disks are μs = 0.80 and μk = 0.60, respectively. disk b is initially stationary when contact with disk a is established by application of the constant force p = 3 lb. determine the angular acceleration α of b and the time t required for b to reach its steady‐state speed.