In a vacuum, the mass of an object DOES NOT determine its rate of fall.

* Galileo's Experiment: Legend has it that Galileo dropped objects of different masses from the Leaning Tower of Pisa to demonstrate this. In a vacuum, a feather and a bowling ball would fall at the same rate.

* Why? Gravity exerts the same force on every object, regardless of its mass. This force causes acceleration. The key is that heavier objects have more inertia (resistance to change in motion). While gravity pulls harder on a heavier object, the heavier object also resists acceleration more, resulting in the same rate of fall.

In the real world, air resistance plays a significant role.

* Air resistance: The force of air pushing against an object depends on its shape, size, and speed. A feather experiences a lot of air resistance, while a bowling ball experiences less. This is why a feather falls much slower than a bowling ball in normal air.

Key Takeaway:

In a vacuum, mass doesn't affect the rate of fall. However, in the real world, air resistance significantly impacts how fast objects fall.