Fluid friction is the kind of friction between the skydiver and the air.
Step-by-step explanation:
Objects moving through fluid experience fluid friction or drag. A skydiver diving in air is an example of fluid friction since air as a medium is fluid and thus air molecules resists the falling motion of a body. Weight of the object due to gravity decides the acceleration of a skydiver when in flight and the resisting frictional force (drag), opposes it.
So, a resultant force acts and his velocity increases proportionally at first and then becomes a constant terminal value. The extent of fluid friction is dependent on the size of body as well as its speed. Larger the size more is the friction; higher the speed more is the friction.