Question

A small stone and a heavy brick are dropped from the roof of an appartment at the same time. Assume no air resistance on the bodies, which one of them will reach the ground first ?

• A. Small stone
• B. Heavy brick
• C. Both at same time
• D. Insufficient information

Answer 1

The correct option is C Both at same time

Acceleration due to gravity is given by, $g=\frac{GM}{R^2}$. It value is the same for all objects near Earth's surface.

Given both objects are dropped with zero initial speed from the same point.
Using equation of motion,
$H=\frac{1}{2}g{t}^2$
$t=\sqrt{\frac{2H}{g}}$
Since $H$ and $g$ are same for both the stone and the brick, time is the same.