8.5 Exercise 5

Mass A slides across a rough table with an initial velocity of 12 m/s in the +x-direction. By the time mass A collides with mass B (a stationary object with equal mass), mass A has slowed to 10 m/s. After the collision, the two objects stick together and move as one. Immediately after the collision, the velocity of the system is measured to be 5 m/s in the +x-direction, and the system eventually slides to a stop. Which of the following statements is true about this motion?

1. Momentum is conserved during the collision, but it is not conserved during the motion before and after the collision.
2. Momentum is not conserved at any time during this analysis.
3. Momentum is conserved at all times during this analysis.
4. Momentum is not conserved during the collision, but it is conserved during the motion before and after the collision.