The 50-lb cylinder A is descending with a speed of 20 ft/s when the brake is applied. If...

The 50-lb cylinder A is descending with a speed of 20 ft/s when the brake is applied. If wheel B must be brought to a stop after it has rotated 5 revolutions, determine the constant force P that must be applied to the brake arm. The coefficient of kinetic friction between the brake pad C and the wheel is = 0.5. The wheel's weight is 25 lb, and the radius of gyration about its center of mass is k = 0.6 ft.