F=ma

D=m/V

m=VD

a = dv/dt

F=VDdv/dt

= Volume * Density * (change in velocity) / (change in time)

= (Volume of Air Moved) * (Density of the Air) * (the final velocity of the air) / (change in time)

(final velocity of the air) = ??? (How do you determine this? It's elastic collision I'm guessing?? But I don't know what to do...)