Question

A rock is dropped from the top of a tall tower. Half a second later another rock, twice as massive as the first, is dropped. Ignoring air resistance, 

(A) the distance between the rocks increases while both are falling. 

(B) the acceleration is greater for the more massive rock. 

(C) the speed of both rocks is constant while they fall. 

(D) they strike the ground more than half a second apart. 

(E) they strike the ground with the same kinetic energy.

Answer 1

Correct option (A) the distance between the rocks increases while both are falling.

Eliminating obviously wrong choices only leaves A as an option. The answer is A because since the first ball has a head start on the second ball it is moving at a faster rate of speed at all times. When both are moving in the air together for equal time periods the first faster rock will gain more distance than the slower one which will widen the gap between them.