The truck at B is used to hoist the cabinet up to the fourth floor of a building using the rope and pulley arrangement. The truck has a speed of vB = 2 ft/s, and is accelerating at aB = 0.6 ft/s2. Determine the acceleration of the cabinet when sA = 40 ft. Note that when sB = 0, sA = 0 (points A and B are coincident).