The motor at C pulls in the cable with an acceleration aC = (3t2) m/s2, where t is in seco...

The motor at C pulls in the cable with an acceleration aC = (3t2) m/s2, where t is in seconds. The motor at D draws in its cable at aD = 5 m/s2. If both motors start at the same instant from rest when d = 3 m, determine (a) the time needed for d = 0, and (b) the velocities of blocks A and B when this occurs.