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 Rider and obstacles on the road. The up and down buttons are used to shift gears. Mach Rider's bike has four speeds and shifting to the fourth gear at high speed will grant the player in instant speed boost. Conversely, the player remaining in a higher gear while stopping results in a slower acceleration. In each round, points can be scored by destroying enemies and certain obstacles with the machine gun. The number of points scored for destroying enemies and obstacles is determined by the type of enemy or obstacle destroyed. If the player blocks an attacking enemy by ramming it