Here's why:
* Gravity: In a vacuum, the only force acting on both the marble and the paper is gravity. Gravity accelerates all objects at the same rate, regardless of their mass or shape. This acceleration due to gravity is approximately 9.8 m/s² near the Earth's surface.
* Air Resistance: In normal air, the paper experiences significantly more air resistance than the marble due to its larger surface area. This resistance slows the paper down, making it appear to fall slower.
* Vacuum eliminates air resistance: In a vacuum, there is no air to resist the fall of either object. Therefore, both the marble and the paper will fall at the same rate and reach the ground simultaneously.
The famous experiment: This principle was famously demonstrated by Apollo 15 astronaut David Scott on the Moon, where there is essentially no atmosphere. He simultaneously dropped a feather and a hammer, and they both landed at the same time, proving that gravity acts equally on all objects.
