Ran through Wikipedia and Google quickly and came up with this:
Drag force = (1/2) * p * v^2 * CoD * A
- p = air density
v = velocity
CoD = Coefficient of Drag
A = relative area
Fill in with measurements:
Drag force = (1/2) * 1.204 kg/m^3 * (12.8016 m/s)^2 * 0.4 * 0.0162146393 m^2 = 2.010 Newtons (approx. 0.452 pounds).
Fairly negligible if my math is right. Mathematically, you could figure out how much force is needed to have the ball travel at a speed without regarding drag, then just tack the drag force onto that. Making something to force a ball to go at that speed will be hard, though.
EDIT1: Fixed a stupid math error (00:49)
EDIT2: Check out
this post on drag etc. (01:13)