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The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. More simply, the speed of sound is how fast vibrations travel. At 20 °C (68 °F), the speed of sound in air, is about 343 m/s (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn), or 1 km in 2.91 s or one mile in 4.69 s.
The speed of sound increases with air temperature, so at Mach 0.83 at 3,000 m (10,000 ft) where the air is much warmer than at 9,100 m (30,000 ft), the true airspeed at M MO would be 982 km/h (530 kn).
c is the speed of sound in the medium, which in air varies with the square root of the thermodynamic temperature. By definition, at Mach 1, the local flow velocity u is equal to the speed of sound. At Mach 0.65, u is 65% of the speed of sound (subsonic), and, at Mach 1.35, u is 35% faster than the speed of sound (supersonic).
Those physical properties and the speed of sound change with ambient conditions. For example, the speed of sound in gases depends on temperature. In 20 °C (68 °F) air at sea level, the speed of sound is approximately 343 m/s (1,230 km/h; 767 mph) using the formula v [m/s] = 331 + 0.6 T [°C].
A sonic boom produced by an aircraft moving at M=2.92, calculated from the cone angle of 20 degrees. Observers hear nothing until the shock wave, on the edges of the cone, crosses their location. A Mach wave propagates across the flow at the Mach angle μ , which is the angle formed between the Mach wave wavefront and a vector that points ...
Thus speed of sound in gases with higher molar mass have lower speed of sound). -- Jon Ayre 14:20 9th Dec 2005 (GMT) 331.5+0.607*T(degrees celsius) meters/second. -- Monohouse 2006 The linear formula commonly used for the speed of sound as a function of temperature is the first-order approximation of the square root formula.
<614 mph (988 km/h; 274 m/s) Most often propeller-driven and commercial turbofan aircraft with high-aspect-ratio (slender) wings, and rounded features like the nose and leading edges. The subsonic speed range is that range of speeds within which, all of the airflow over an aircraft is less than Mach 1.
In dry air at 20 °C (68 °F), the speed of sound is 343 metres per second (about 767 mph, 1234 km/h or 1,125 ft/s). The term came into use during World War II when pilots of high-speed fighter aircraft experienced the effects of compressibility , a number of adverse aerodynamic effects that deterred further acceleration, seemingly impeding ...