One object is traveling northeast with a momentum of 12 kg-m/s, while a second object is traveling southwest on the same path as the first object with a momentum of 4 kg-m/s. When the two objects collide, they stick together. What is the momentum after their collision?

Question

8 kg-m/s northeast
16 kg-m/s northeast
8 kg-m/s southwest
16 kg-m/s southwest

Answer 1

The momentum of the first object is 12 kg-m/s northeast, and the momentum of the second object is 4 kg-m/s southwest. Since they are traveling in opposite directions, their momenta are in different directions, so we need to treat the momentum of the second object as negative.

After the collision, the two objects stick together, so their momenta are combined. The momentum after the collision is the sum of the momenta before the collision.

12 kg-m/s - 4 kg-m/s = 8 kg-m/s northeast

Therefore, the momentum after the collision is 8 kg-m/s northeast.