2.(35%) A centrifugal clutch (離心式離合器）shown has a constant angular velocity of 3000 rpm. Thin curved members AB and CD are connected by pins at A and C to the arm AC which rotates about a fixed point O. Each of the members AB and CD has a mass of 5 g and a radius of 10 inch. As the clutch rotatescounterclockwise, two knobs located 30。slide on the inside of a fixed cylindrical surface of radius 11 mm with the coefficient of kinetic Ihction is 0.35. Determine the couple M which must be applied to arm AC. Hint： The distance from the centroid (質量中心）of curved members AB (or CD) to the fixed point O is 7.379 mm.