Скачать или смотреть What is drag force?

The force on an object that resists its motion through a fluid is called drag. When the fluid is a gas like air, it is called aerodynamic drag or air resistance. When the fluid is a liquid like water it is called hydrodynamic drag, but never "water resistance".

In fluid dynamics, drag, sometimes referred to as fluid resistance, is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid.

Drag is a mechanical force. It is generated by the interaction and contact of a solid body with a fluid (liquid or gas).

Drag is a force exerted by a fluid stream on any obstacle in its path or felt by an object moving through a fluid. Its magnitude and how it may be reduced are important to designers of moving vehicles, ships, suspension bridges, cooling towers, and other structures. Drag forces are conventionally described by a drag coefficient, defined irrespective of the shape of the body.