Air resistance, also known as drag, is a force that opposes the motion of an object moving through the air. It occurs because air molecules collide with the surface of the object, creating friction. The faster an object moves, the greater the air resistance it experiences. This force is significant for objects like cars, airplanes, and falling objects. Air resistance affects how quickly an object can accelerate or decelerate. For example, a parachute increases air resistance, allowing a person to descend slowly and safely. In contrast, a streamlined shape, like that of a sports car, reduces air resistance, enabling faster speeds and better fuel efficiency.