Fact 1: The vanes rotating in an electric fan causes air to move.

Fact 2: Output of the fan is varied by means of a series of adjustable vanes upstream of the impeller.

Given the two facts above, answer the question "what is fan speed?" with the following options: 
- energy barrier
 - kinetic energy
 - fixed
 - cycles
 - Winter
 - static
 - solid
 - adjustable


 

        adjustable 