A 20 kg cart traveling to the right at 12 m/s collides head on with a 10 kg cart traveling 6 m/s to the left. After the collision, the 10 kg cart is traveling 10 m/s to the right. A) What is the velocity of the 20 kg cart after the collision? b) Determine whether or not the collision is elastic. C) Are the answers in A & B reasonable.