单词	Mach
释义	Mach /mɑːk / /mak / (also Mach number) noun The ratio of the speed of a body to the speed of sound in the surrounding medium. It is often used with a numeral (as Mach 1, Mach 2, etc.) to indicate the speed of sound, twice the speed of sound, etc.A Mach number is a measure of airspeed, and not of ground speed.... When the P - 38 wing developed a supersonic enclosure at the critical Mach number, the center of pressure moved aft, causing the nose to tuck down. The party atmosphere as we roared across the Atlantic at twice the speed of sound, Mach 2, 1,350 miles per hour, at the very edge of space. Origin 1930s: named after Ernst Mach (see Mach, Ernst).
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