Mach number
Ratio of the speed of a body to the speed of sound in the medium through which the body travels. In the Earth's atmosphere, Mach 1 is reached when a body (such as an aircraft or spacecraft) ‘passes the sound barrier’, at a velocity of 331 m/1,087 ft per second (1,192 kph/740 mph) at sea level. A space shuttle reaches Mach 15 (about 17,700 kph/11,000 mph an hour) 6.5 minutes after launch.
The Mach number is named after Austrian physicist Ernst Mach.
The Mach number is named after Austrian physicist Ernst Mach.
© RM 2012. Helicon Publishing is division of RM.
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