Mach wave Mach wave In fluid dynamics, a Mach wave is a pressure wave traveling with the speed of sound caused by a slight change of pressure added to a compressible flow. These weak waves can combine in supersonic flow to become a shock wave if sufficient Mach waves are present at any location. Such a shock wave is called a Mach stem or Mach front. Thus, it is possible to have shockless compression or expansion in a supersonic flow by having the production of Mach waves sufficiently spaced ("cf." isentropic compression in supersonic flows). A Mach wave is the weak limit
Mach Five "Mach 6", two different single-seater cars created specifically for stunt races. The designs of the Mach 4 and Mach 6 are vaguely reminiscent of the Mach Five's (as in the original American comics), although the only functions the Mach 6 features are the jump jacks, which are standard equipment in race cars in the movie. Little about the Mach 4 is known, as it appears only briefly in the film and is portrayed as a red-colored companion to the 6. The film portrays the Mach Five as initially being a regular everyday vehicle, justifying the existence of its trunk door