SPEED OF SOUND
The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at 20 °C (68 °F),
the speed of sound is 343.2 metres per second (1,126 ft/s). This is
1,236 kilometres per hour (768 mph), or about one kilometer in three
seconds or approximately one mile in five seconds.
In fluid dynamics,
the speed of sound in a fluid medium (gas or liquid) is used as a
relative measure of speed itself. The speed of an object (in distance
per time) divided by the speed of sound in the fluid is called the Mach number. Objects moving at speeds greaterkly depends oy
for a given ideald speed is slightly depependent on square root of the
mean molecular weight of the gas, and affected to a lesser extent by the number of ways in which the molecules of the gas can store heat from compression, nd in gaxpressed in terms of a ratio of both
density and pressure, these quantities cancel in ideal gases at any
given te only the latter independent
In common everyday speech, speed of sound refers to the speed oaves in air. However, the speed of sounstance to substance. Sound t in liquids aoli it does in air. It travels about 4.3 times as fast in water
(1,484 m/s), and nearly 15 times on (5,1 The speed of shear waves is determined only by the solid material's shear modulus and density.