Mach number temperature generally decreases with increasing altitude between sea level and , the speed of sound also decreases. For example, the standard atmosphere model lapses temperature to at altitude, with a corresponding speed of sound (Mach1) of , 86.7% of the sea level value. While the terms "subsonic" and "supersonic", in the purest sense, refer to speeds below and above the local speed of sound respectively, aerodynamicists often use the same terms to talk about particular ranges of Mach values. This occurs because of the presence of a "transonic regime" around M = 1 where approximations of the Navier-Stokes equations used
Mach Five car appeared to have the same functions as the Mach Five in the original series, but the buttons Speed pressed to activate them seemed more or less random, with the same button activating different abilities (or different buttons activating the same ability) in different episodes. In 2000, a prototype Mach Five with actual cutting blades was produced as a concept car. 100 production models were planned to be made in 2002 as a street legal vehicle. Built on a 2001 Chevrolet Corvette Chassis, the body was to be extensively modified to look like the Mach Five. It was to have