* Gravity and Air Resistance: When an object falls, gravity pulls it down, causing it to accelerate. However, as the object falls faster, it encounters more air resistance. This resistance force acts in the opposite direction of the object's motion.

* Balancing Forces: As the object accelerates, the force of air resistance increases until it eventually equals the force of gravity. At this point, the net force on the object becomes zero.

* Constant Velocity: With no net force, the object stops accelerating and continues falling at a constant speed, which is its terminal velocity.

Factors Affecting Terminal Velocity:

* Object's Shape and Size: A more streamlined shape or a smaller surface area reduces air resistance, leading to a higher terminal velocity.

* Object's Mass: A heavier object experiences a stronger gravitational force, but air resistance also increases proportionally. The effect of mass on terminal velocity is less direct.

* Density of the Air: Thicker air creates more resistance, resulting in a lower terminal velocity.

Important Note: Terminal velocity is not a fixed value. It depends on the factors mentioned above and varies for different objects in different conditions.