Question

You have two golf balls that differ only in their surfaces. one has dimples, while the other is smooth. if you were to drop the balls simultaneously from the top of the eiffel tower, which will hit the ground first?

Answer 1

Answer: the golf ball with smooth surface would hit the ground first.

Jusitification:

An analysis of forces show two vertical forces acting on the golf balls.

1) one force is the weight (mg) which is vertical downward

2) the other force is the drag force exerted by the air on the golf balls, and it is vertical upward.

3) the drag force opposes the weight, so the acceleration downward is determined by the difference of the weiight and the drag force, until the balls reach the terminal speed (when the drag force equals the weight).

4) the drag force depends on the shape and area of the object falling. Being the surface of one ball smooth implies that the drag force will be less than the one on the other ball.

5) less drag force implies that the terminal velocity of the smooth ball will he higher, ant then it will hit the ground first.