Mach number which was also unit-first, and may have influenced the use of the term Mach. In the decade preceding faster-than-sound human flight, aeronautical engineers referred to the speed of sound as "Mach's number", never "Mach 1". Mach number is useful because the fluid behaves in a similar manner at a given Mach number, regardless of other variables. As modeled in the International Standard Atmosphere, dry air at mean sea level, standard temperature of , the speed of sound is . The speed of sound is not a constant; in a gas, it increases as the absolute temperature increases, and since atmospheric
Kawasaki S1 Mach I Mach I emerged nearly one year after its bigger brother, the S2 Mach II 350, and from the development success of the Kawasaki H1 Mach III. It was essentially the same motorcycle as its larger brother with less displacement. It had a separate handlebar holder and steering friction damper. Its successor, the KH250, was essentially the same bike with a different name, was marketed from 1976 to 1981. Kawasaki S1 Mach I The Kawasaki Mach I (model designation S1) was a Kawasaki motorcycle made 1972 through 1975. The Mach I was a direct result of the widespread success of the