Final answer:
Two objects with the same mass may not reach the ground at the same time due to air resistance. Mass affects the force of air resistance, causing objects with larger surface areas to fall slower.
Step-by-step explanation:
When two objects with the same mass are dropped from the same height, they may not reach the ground at the same time due to the presence of air resistance.
Although mass does not affect the rate of free fall in the absence of air resistance, it does affect the force of air resistance experienced by the objects.
Objects with larger surface areas experience greater air resistance, causing them to fall slower than objects with smaller surface areas.
For example, if we drop a feather (which has a larger surface area) and a marble (which has a smaller surface area) from the same height, the feather will experience more air resistance and take longer to reach the ground compared to the marble.
On the Moon, where there is no atmosphere and therefore no air resistance, objects with the same mass will indeed reach the ground at the same time.