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
Mach Five Mach Five The is the racing car Speed Racer (Go Mifune in the Japanese version) drives in the anime series of the same name (known as ""Mach Go! Go! Go!"" in Japan). The car was designed, built, and created by "Pops Racer" (Daisuke Mifune), Speed Racer's father. It features a set of special devices which Speed Racer uses throughout the series. In the original 1967 series, the Mach Five is a white racing car with an "M" written on its hood (which does not stand for "Mach 5", but instead stands for "Mifune", both Go's last name, and the name