6000 N M 20° B 20°

Could you go step by step on how to solve this problem. I've been tackling it for the past few hours and I can't seem to get it quite right.

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??

The green rods apply a 2.6 kN clamping force to the red object, E. The square-threaded screw used to generate the clamping force passes through a threaded opening at B and presses against lever ACE at E. The coefficient of static friction is = 0.29. Neglect friction at A. The screw has mean radius r = 9 mm and lead L = 2 mm. B 180 mm 70 mm E (a) Determine the force in member CD in kilonewtons. (Enter the magnitude.) kN (b) Determine the magnitude of the moment in N• m that one must apply to the screw to increase the clamping force. N: m (c) Determine the magnitude of the moment in N •m that one must apply to the screw to decrease the clamping force. N: m