Question

Two metal balls are the same size but one weighs twice as much as the other. The balls are dropped from the roof of a single story building at the same instant of time. The time it takes the balls to reach the ground below will be:___________

a) about half as long for the heavier ball as for the lighter one.
b) about half as long for the lighter ball as for the heavier one.
c) about the same for both balls.
d) considerably less for the heavier ball, but not necessarily half as long.
e) considerably less for the lighter ball, but not necessarily half as long.

Answer 1

c) about the same for both balls.

Step-by-step explanation:

This is a very peculiar problem. It seems very easy. You might think that the heavier ball will reach first because its heavier. But it does not. In fact, both the balls will reach at the same time.

The reason is acceleration due to gravity. The time that the balls will take to reach the ground depends mainly on the initial velocity and acceleration. Since initial velocity is zero for both of them so the only factor governing their drop is acceleration due to gravity. Acceleration due to gravity is same for both the balls irrespective of their weight. Thus they will reach the ground at the same time.