A classical mechanics problem by Vishwas H K

The earth's gravitational force over an falling object depends on the mass of the object and the mass of earth minus the mass of the object. As the mass of the object is very small compared to earth's one, in a simple problem it's neglectible, so we can say that the gravitational force over an falling object is independent of it's mass. To take the final conclusion the other thing we should consider is that the object is ponctual so the air resistance don't take part in our problem. Finally, considering this aproximations, the balls will fall at the same time.

Neglecting air resistance or any other external force any body be it on earth , moon , Jupiter will take same time to reach the same distance. At earth the air molecules in our atmosphere creates a drag force which opposes the motion and increases the time the force will depend upon surface area in contact whereas moon doesn't possess atmosphere so there both will reach in same time.

All the objects on the earth experience the same level of gravitational force. So the mass of an object doesn't effect the gravitational force. So the two balls will reach the earth at the same time.