Blocks A and B have masses { m }_{ A } and { m }_{ B } respectively. They are placed on a smooth surface and the spring connected between them is stretched a distance d. If they are released from rest, determine the speeds of both blocks the instant the spring becomes unstretched. Given: { m }_{ A } = 40 kg , d = 2 m , { m }_{ B } = 60 kg , k = 180 N/m