* Free Fall: Free fall means an object is only under the influence of gravity. No other forces, like air resistance, are significantly acting on it.

* Air Resistance: Air resistance is a force that opposes the motion of an object through the air. The more surface area an object has and the faster it's moving, the greater the air resistance.

* Acceleration: Acceleration is the rate of change of velocity. In free fall, the acceleration due to gravity is constant (approximately 9.8 m/s² on Earth).

How it works:

* An object with less air resistance experiences less force opposing its downward motion.

* With less opposing force, gravity has a greater effect on the object, leading to a larger acceleration.

Example:

* A feather and a bowling ball dropped from the same height. The feather has much more air resistance, so it falls slower and accelerates less. The bowling ball has less air resistance, so it falls faster and accelerates more.

Important Note: In a true vacuum (where there is no air), all objects would fall at the same rate regardless of their mass or shape because there would be no air resistance.