Mach number (Ma) (pronounced: [m??k], [m?x], [mæk], see IPA) is a dimensionless measure of relative speed. It is defined as the speed of an object relative to a fluid medium, divided by the speed of sound in that medium. Mach number is the number of times the speed of sound an object or a duct, or the fluid medium itself, move relative to each other. It is named after Austrian physicist and philosopher...