A simplified disk brake assembly is shown. A force F = 30 lb is applied to the lower end of the massless brake lever at a distance d from the lever’s pivot O. The brake is located L = 0.2 ft from O at...

A simplified disk brake assembly is shown. A force F = 30 lb is applied to the lower end of the massless brake lever at a distance d from the lever’s pivot O. The brake is located L = 0.2 ft from O at the upper end of the lever, and the coefficient of friction between the brake and the disk is ? = 0.7. The disk has a weight and radius of W = 120 lb and R = 0.25 ft, respectively, and it is initially spinning at a constant ?o = 1000 rpm. What should d be if the disk is to come to a stop in Δ? = 1??