Ernst Mach of experimental physics concentrated on the interference, diffraction, polarization and refraction of light in different media under external influences. From there followed important explorations in the field of supersonic fluid mechanics. Mach and physicist-photographer Peter Salcher presented their paper on this subject in 1887; it correctly describes the sound effects observed during the supersonic motion of a projectile. They deduced and experimentally confirmed the existence of a shock wave of conical shape, with the projectile at the apex. The ratio of the speed of a fluid to the local speed of sound "v"/"v" is now called the Mach number. It
Ford Mustang Mach 1 a cold air "snorkel" and a partial Ram Air at speed. 2004 saw only minor cosmetic changes to the Mach 1. 2004 Mach 1s can be identified by bare aluminium finished valve covers, as opposed to the 2003's black finished covers. Outside, 2004 Mach 1's wear 40th anniversary tags ahead of the doors while the 2003 has the traditional Mustang Running Pony and Tri-Color bar. The lone interior change was the deletion of the overhead "cargo net" mounted on the headliner. Despite pre-production rumors, the horsepower and torque ratings were not increased in 2004. Power rating was and . With