Mach number Mach number In fluid dynamics, the Mach number (M or Ma) (; ) is a dimensionless quantity representing the ratio of flow velocity past a boundary to the local speed of sound. where: By definition, at Mach1, the local flow velocity is equal to the speed of sound. At Mach0.65, is 65% of the speed of sound (subsonic), and, at Mach1.35, is 35% faster than the speed of sound (supersonic). The local speed of sound, and thereby the Mach number, depends on the condition of the surrounding medium, in particular the temperature. The Mach number is primarily used to determine
Mach Five (rather than having it serve solely as an excuse for Spritle and Chim-Chim to stow away in the vehicle). The Mach Five is later modified with gadgets and becomes Speed's alternate car for off-track races such as the Casa Cristo 5000, as well as everyday driving like a normal car. The Mach Five originally belonged to Speed's older brother Rex, who relinquished ownership of it to Speed before he left the Racer home. Speed's main car for races on the WRL track (Thunderhead, etc.) is the Mach 6. The Mach 6 was destroyed in a fixed race, but was later