sonic speed

sonic speed

[′sän·ik ¦spēd] (acoustics) speed of sound

sonic speed

Speed of sound as a function of altitude.The local speed of sound. In the international standard atmosphere (ISA), sound travels at 761.6 mph, 1116 ft/s, 340.5 m/s, 661.7 knots, 34,046.16 cm/s, or 1225.5 km/h. The speed of sound decreases with altitude, and above the tropopause its value is 295.5 m/s, 574 knots, 658 mph, or 1063.2 km/h. The speed of sound is determined by the density of the medium. In air, it is the temperature that affects the density and the speed of sound. The illustration indicates the values of the speed of sound at various altitudes in the ISA.