A football is kicked off a tee. A baseball player slides into second base. A floating stick is carried over a waterfall. A bicycle travels faster as it goes downhill.
I gave my students this multiple choice question: Newton's first law of motion states that an object at rest will stay at rest unless acted upon by an outside force. Which activity is an example of this law?

Only one answer is correct among these 4 choices:
- A football is kicked off a tee.
- A baseball player slides into second base.
- A floating stick is carried over a waterfall.
- A bicycle travels faster as it goes downhill.

Could you tell me which one is correct?

A football is kicked off a tee.