What is meant by free fall? Two bodies,one of mass $1\,g$ and other of mass $1\,kg$,are dropped from the same height in a vacuum. Compare the two time intervals in which the two bodies will hit the ground.

(A) Free fall is defined as the motion of an object falling towards the Earth solely under the influence of gravitational force,with no other forces like air resistance acting upon it.
In a vacuum,there is no air resistance. The acceleration experienced by any object falling freely is the acceleration due to gravity $(g)$,which is approximately $9.8\,m/s^2$ near the Earth's surface.
Since the acceleration due to gravity $(g)$ is independent of the mass of the falling object,both bodies will experience the same acceleration.
Using the equation of motion $s = ut + \frac{1}{2}at^2$,where $u = 0$ (initial velocity) and $s = h$ (height),we get $h = \frac{1}{2}gt^2$,which implies $t = \sqrt{\frac{2h}{g}}$.
Since $h$ and $g$ are the same for both bodies,the time taken $(t)$ will be identical for both. Therefore,both bodies will hit the ground at the same time.