The force that opposes the movement of an object in air is called air resistance or drag.

Here's a breakdown:

* Air resistance is a type of friction that occurs when an object moves through the air.

* Drag is a more general term that refers to any force that opposes motion in a fluid (like air or water).

Air resistance depends on several factors:

* Speed: The faster the object moves, the greater the air resistance.

* Shape: A streamlined object (like a bullet) encounters less air resistance than a blunt object (like a parachute).

* Surface area: A larger surface area exposed to the air means more air resistance.

* Density of the air: Denser air (like at higher altitudes) provides more resistance.

Let me know if you'd like more details about how air resistance works!