what is the speed of the sound in air
Speed of sound The speed of sound is the distance travelled per unit time by a sound wave as it propagates through an elastic medium. In dry air at 0 °C (32 °F), the speed of sound is 331.2 metres per second (1,087 ft/s; 1,192 km/h; 741 mph; 644 kn). At 20 °C (68 °F), the speed of sound is 343 metres per second (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn), or a kilometre in 2.91 s or a mile in 4.69 s.
Sound barrier Meanwhile, test pilots achieved high velocities in the tailless, swept-wing de Havilland DH 108. One of them was Geoffrey de Havilland, Jr. who was killed on 27 September 1946 when his DH 108 broke up at about Mach 0.9.[26] John Derry has been called "Britain's first supersonic pilot"[27] because of a dive he made in a DH 108 on 6 September 1948.