The second type of frictional force acting on a skier is drag. This is typically referred to as " air resistance ". The drag force is proportional to the cross-sectional area of a body (e.g. the skier) and the square of its velocity and density relative to the fluid in which the body is traveling through (e.g. air). To go faster, a skier can try to reduce the cross-sectional area of their body. Downhill skiers can adopt more aerodynamic positions such as tucking. Alpine ski racers wear skin tight race suits. The general area of physics which addresses these forces is known as fluid dynamics.