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Yeah, the *force* needed to overcome aero drag is the square of the velocity, the *power* required to overcome aero drag is the cube of the velocity.  We always used the power equation in our presentations because EPA engine emissions standards are expressed in units of mass emissions per power output (usually gm/brake-horsepower-hr), so we expected that emissions improvements due to lowering drag were more related to power output, at least for the stuff we were testing, which was lowering drag.