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
Ford Mustang Mach 1 1 models of the previous four years. The 302 Windsor returned in 1975, rated at and of torque, giving the Pinto platform a notable performance boost. Also available was a 4-speed manual. The Mach 1 remained mostly unchanged in 1976, as a new performance model - the Cobra II - was introduced alongside. 1977 proved to be the weakest sales year of the Mach 1 to date, selling only 6,719 units. The nameplate remained for one more year, upon when it was discontinued with the advent of the third generation Mustang in 1979. During the 1990s, the preeminent performance Mustang