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 than six factory performance Mustang models were available (GT, Boss 302, Boss 429, Shelby GT350, Shelby GT500 and the Mach 1). Additionally, seven variations of V-8s were available in the '69–'70 models; most of these also available in the new Mach 1. Due to the Mach 1's success, the GT model was discontinued after 1969 following poor sales of 5,396 units versus the 72,458 sales for the Mach 1. The Mustang would not wear the "GT" badge again until 1982. The Mach 1 package was only available in the 'SportsRoof' body style (previously known as the 'Fastback'); never on the