You are riding a luxury bus. In front of you is a cup of tea resting on the seat-back tray. Which of the following events may lead to spilled tea in your lap? Don't worry about other circumstances such as a person knocking your cup over. (Select all that apply.) The bus speeds up.
The bus remains at rest.
The bus moves at constant velocity.
The bus slows down.

Explain your answers. (Select all that apply.)
The cup spills any time the bus is in motion.
The cup will not spill in your lap if it tips away from you.
The cup will spill only when the bus accelerates.
The cup will not spill due to the bus's motion.