Gravity increases as the basketball bounces. The floor adds energy to the bouncing basketball. Energy is transferred from the basketball to the floor. The air inside the basketball is heavier than the surrounding air.
I gave my students this multiple choice question: A basketball bounces on the gym floor nine times and finally comes to a rest. Which of these best explains why the basketball rises to a lower height each time it bounces?

Only one answer is correct among these 4 choices:
- Gravity increases as the basketball bounces.
- The floor adds energy to the bouncing basketball.
- Energy is transferred from the basketball to the floor.
- The air inside the basketball is heavier than the surrounding air.

Could you tell me which one is correct?

Energy is transferred from the basketball to the floor.