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
Kawasaki H2 Mach IV Kawasaki H2 Mach IV The Kawasaki H2 Mach IV was a 750 cc 3-cylinder two-stroke production motorcycle manufactured by Kawasaki. The H2 was a Kawasaki triple sold from September 1971 through 1975. A standard, factory produced H2 was able to travel a quarter mile from a standing start in 12.0 seconds. It handled better than the Mach III that preceded it. By the standards of its time, its handling was sufficient to make it the production bike to beat on the race track. Nonetheless, its tendency to pull wheelies and a less than solid feel through high speed corners led