Given: A homogeneous circular disk (having a mass of m and outer radius of R) is pinned to ground with a smooth pin at O. An inextensible cable is wrapped over the outer surface of the disk. One end of the cable supports block A (of mass 2m), and the other end of the cable B is connected to ground with a spring of stiffness k, as shown below. Assume that the cable does not slip on the disk and that the cable remains taut for all motion. Let 0 describe the rotation of the disk, and let the spring be unstretched when = 0. Find: For this problem, derive the differential equation of motion for the system in terms of the coordinate. g 2m B m