A student claims that in the absence of air resistance, all objects, whatever be their masses, fall with the same acceleration towards the Earth. Answer the following questions to examine this claim.
(i) Define the term "free fall".
(ii) Give a brief explanation to justify why a heavy iron ball and a light tennis ball dropped from the same height reach the ground at the same time when air resistance is negligible.
(iii) State any two reasons why, in ordinary classroom conditions, a feather released from the same height takes a much longer time to reach the floor than an iron nail.
(iv) Predict what would happen if the feather and the nail were dropped together on the surface of the Moon. Give one reason for your answer.