# AP Physics 1 Question 100: Answer and Explanation

### Test Information

Question: 100

10.

Question below refers to the following information:

Block B is at rest on a smooth tabletop. It is attached to a long spring, which in turn is anchored to the wall. Identical block A slides toward and collides with block B. Consider two collisions, each of which occupies a duration of about 0.10 s:

Collision I: Block A bounces back off of block B.

Collision II: Block A sticks to block B.

In which collision, if either, does block B move faster immediately after the collision?

• A. In collision I, because block A experiences a larger change in momentum, and conservation of momentum requires that block B does as well.
• B. In collision I, because block A experiences a larger change in kinetic energy, and conservation of energy requires that block B does as well.
• C. In neither collision, because conservation of momentum requires that both blocks must have the same momentum as each other in each collision.
• D. In neither collision, because conservation of momentum requires that both blocks must change their momentum by the same amount in each collision.