8.4 Exercise 9

Two objects, A and B, have equal mass. Prior to the collision, mass A is moving 10 m/s in the +x-direction, and mass B is moving 4 m/s in the +x-direction. Which of the following results represents an inelastic collision between A and B?

1. After the collision, mass A is at rest, and mass B moves 14 m/s in the +x-direction.
2. After the collision, mass A moves 4 m/s in the –x-direction, and mass B moves 18 m/s in the +x-direction.
3. After the collision, the two masses stick together and move 7 m/s in the +x-direction.
4. After the collision, mass A moves 4 m/s in the +x-direction, and mass B moves 10 m/s in the +x-direction.