1) In everyday language, 'free falling' usually describes objects moving directly towards the ground. Explain how an object like a tennis ball thrown upward can technically be free falling even though it is not moving towards the ground.
2) What is the meaning of free as used in the expression free fall?
3) Will rides in an airplane flying straight and level. Mary stands on the ground. Both drop a marble and observe their own marble as it falls. Is there any difference between how the fall of Will's marble looks to Will and how the fall of Mary's marble looks to Mary?
4) Galileo studied free fall to help him decide whether or not earth is moving through space as it orbits the sun. How does the study of free falling objects on earth inform us on the motion or lack thereof of the earth?
5) Which free falls faster; one brick or two bricks?