Skydiving!
Air resistance (or drag) is an example of a dissipative force. An object falling in air experiences a drag force that depends on the speed of the falling body, the air density and the surface area of the falling object. If the flow around the body is turbulent (the air flow breaks into swirls), the magnitude of the drag force is empirically
![\[ D = \frac{1}{2}C \rho A v^2, \]](mastermathpng-0.png)
where C is the drag coefficient (typically of order 1), A the surface area of the body perpendicular to the falling direction, ρ the air density and v the falling speed.
By changing the shape of his body, a skydiver can alter his effective surface area, his terminal speed and really fly through the air. Some skydivers are so skillful that they can risk jumping without a parachute, collecting one from a friend on the way down. (Warning: Don’t try this at home!!).