13. In the figure, two masses, M = 16 kg and m = 12.8 kg, are connected to a very light rigid bar and areattached to an ideal massless spring of spring constant 100 N/m. The system is set into oscillationwith an amplitude of 78 cm. At the instant when the acceleration is at its maximum, the 16-kg massseparates from the 12.8-kg mass, which then remains attached to the spring and continues tooscillate. What will be the amplitude of oscillation of the 12.8-kg mass?