How Fast Is Mach 1?

Based on the standard atmospheric model, Mach 1 is 761.2 miles per hour at sea level. The speed changes based on temperature and at altitude the temperature is lower than sea level. Based on this, the speed of Mach 1 is estimated at 660.1 miles per hour. You can find more information here: http://www.aerospaceweb.org/question/atmosphere/q0102c.shtml
Q&A Related to "How Fast Is Mach 1"
 Mach 1 is the speed of sound, which varies by the air's pressure and temperature. Mach 1 at sea level is 340.3 m/s, 761.2 mi/h, 1,225 km/h http://wiki.answers.com/Q/How_Fast_is_a_Mach
 Mach 1 = 340.29 m / s. It's the speed of sound! http://www.chacha.com/question/how-is-fast-is-mach...
 Mach 1 is the speed of sound, which is 332 m/s or 1195 km/hr or 717 miles/hour. Mach numbers are named after an Austrian philosopher, Ernst Mach (1838-1916) report this answer. Updated http://www.kgbanswers.com/how-fast-is-mach-1/42235...
 Mach 1, or mach velocity is the speed that sound travels. When you hit mach speed, you rip through the sound barrier creating a sonic boom (Hence the name of a certain blue hedgehog http://uk.answers.yahoo.com/question/index?qid=200...