Two bodies of mass m1 = 1 kg and m2 = 3 kg are connected to each other by a rope as in the figure; m1 is also attached to a spring with spring constant k = 100 N/m and rest length d = 1 m. At the instant t = 0, with the spring at rest and with zero initial velocity, the system is left free to move. In the absence of friction, determine: a) the equations of motion for the system of the bodies x(t); b) the maximum value of the tension in the rope.