Question

A bunch of feathers and a stone of the same mass are released simultaneously in air. Which will fall faster and why ? How will your observation be different if they are released simultaneously in vacuum ?

Answer 1

A stone falls faster.
Because the volume of stone is less than the volume of bunch of feathers of the same mass, the upthrust due to air on stone is less than that on the bunch of feathers, and hence, the stone falls faster.
However, in vacuum, both shall fall together because there will be no upthrust.