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 1 Racing standings, he left the team for Jackson Bros. Motorsports, taking Skoal and No. 33 with him. In 1989, Mach 1 switched to the No. 66 and signed rookie driver Rick Mast. In their first race together, the Daytona 500, Mast drove the unsponsored car to a sixth-place finish, an accomplishment he later said was the one he was the most proud of. Mast and Mach 1 ran twelve more races together that season, they were unable to duplicate that effort. Needham closed the team and sold it to their crew chief, Travis Carter. Travis Carter Motorsports entered NASCAR competition in