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  2. Speed of sound - Wikipedia

    en.wikipedia.org/wiki/Speed_of_sound

    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.

  3. List of conversion factors - Wikipedia

    en.wikipedia.org/wiki/List_of_conversion_factors

    km/h ≡ 1 km/h = 2. 7 × 10 −1 m/s knot: kn ≡ 1 nmi/h = 1.852 km/h = 0.51 4 m/s knot (Admiralty) kn ≡ 1 NM (Adm)/h = 1.853 184 km/h [29] = 0.514 77 3 m/s mach number: M: Ratio of the speed to the speed of sound [note 1] in the medium (unitless). ≈ 340 m/s in air at sea level ≈ 295 m/s in air at jet altitudes metre per second (SI unit ...

  4. Sonic boom - Wikipedia

    en.wikipedia.org/wiki/Sonic_boom

    Therefore, for a boom to reach the ground, the aircraft's speed relative to the ground must be greater than the speed of sound at the ground. For example, the speed of sound at 30,000 feet (9,100 m) is about 670 miles per hour (1,080 km/h), but an aircraft must travel at least 750 miles per hour (1,210 km/h) (Mach 1.12) for a boom to be heard ...

  5. True airspeed - Wikipedia

    en.wikipedia.org/wiki/True_airspeed

    TAS can be calculated as a function of Mach number and static air temperature: =, where is the speed of sound at standard sea level (661.47 knots (1,225.04 km/h; 340.29 m/s)),

  6. Sound - Wikipedia

    en.wikipedia.org/wiki/Sound

    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].

  7. Supersonic speed - Wikipedia

    en.wikipedia.org/wiki/Supersonic_speed

    Supersonic speed is the speed of an object that exceeds the speed of sound (Mach 1). For objects traveling in dry air of a temperature of 20 °C (68 °F) at sea level , this speed is approximately 343.2 m/s (1,126 ft/s; 768 mph; 667.1 kn; 1,236 km/h).

  8. Mach number - Wikipedia

    en.wikipedia.org/wiki/Mach_number

    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). An F/A-18 Hornet creating a vapor cone at transonic speed just before reaching the speed of sound. The local speed of sound, and hence the Mach number, depends on the temperature of the surrounding gas.

  9. Hypersonic speed - Wikipedia

    en.wikipedia.org/wiki/Hypersonic_speed

    921–3,836 mph (1,482–6,173 km/h; 412–1,715 m/s) The supersonic speed range is that range of speeds within which all of the airflow over an aircraft is supersonic (more than Mach 1). But airflow meeting the leading edges is initially decelerated, so the free stream speed must be slightly greater than Mach 1 to ensure that all of the flow ...