Originally Posted by Rob M
not a bad theory.
however, the drag force is a function of the square (not the cube) of the velocity so theoretically the force would be 160 lbs. at 120 mph. but that force may actually be less at speed if there is aerodynamic separation from the vehicle before reaching the spoiler.
I got out my old textbooks, and I guess my memory isn't what it used to be. Yes, the drag is a function of the velocity squared.