Two carts sit on a level, frictionless track and are connected by a compressed spring and a string. At a certain time, the string is cut and the carts fly apart. Cart A is 3 kg, and cart B is 2 kg. After the carts separate, cart A has velocity 0.2 m/s to the left. Take the system to mean carts A and B, and let "right" to be positive.
What is the velocity of cart B after the string is cut?