The speed an object reaches when the force of gravity is balanced by air resistance is called terminal velocity.

Here's why:

* Gravity: Pulls the object downwards, causing it to accelerate.

* Air Resistance: Opposes the object's motion, increasing as the object goes faster.

As the object falls, it speeds up. This increases air resistance until it eventually equals the force of gravity. At this point, the object stops accelerating and reaches a constant speed, which is terminal velocity.