2006-10-03 18:05:08 · 9 answers · asked by nelson 74 1 in Science & Mathematics ➔ Physics
The Ratio of the Speed of an Object to the Speed of Sound in the Surrounding Medium.Usually around 700 MPH.Named after Ernst Mach, Austrian Physicist, [1836-1916]
2006-10-03 18:23:04 · answer #1 · answered by gvaporcarb 6 · 1⤊ 0⤋
Mach number, a useful quantity in aerodynamics, is the ratio of an object's speed to the speed of sound in the medium through which it is passing (again, usually air). At altitude, for reasons explained, Mach number is a function of temperature.
The Mach number is commonly used both with objects travelling at high speed in a fluid, and with high-speed fluid flows inside channels such as nozzles, diffusers or wind tunnels. As it is defined as a ratio of two speeds, it is a dimensionless number. At a temperature of 15 degrees Celsius, Mach 1 is 340.3 m·s-1 (1,225 km·h-1 or 761.2 mph) in the atmosphere. The mach number is not a constant; it is temperature dependent.
Since the speed of sound increases as the temperature increases, the actual speed of an object travelling at Mach 1 will depend on the fluid temperature around it. Mach number is useful because the fluid behaves in a similar way at the same Mach number. So, an aircraft traveling at Mach 1 at sea level (340.3 m·s-1, 1,225.08 km/h) will experience shock waves in much the same manner as when it is traveling at Mach 1 at 11,000 m (36,000 ft), even though it is travelling at 295 m·s-1 (654.632 MPH, 1,062 km/h, 86% of its speed at sea level).
It can be shown that the Mach number is also the ratio of inertial forces (also referred to aerodynamic forces) to elastic forces.
[edit]
High-speed flow around objects
High speed flight can be classified in five categories:
Subsonic: Ma < 1
Sonic: Ma = 1
Transonic: 0.8 < Ma < 1.2
Supersonic: 1.2 < Ma < 5
Hypersonic: Ma > 5
(For comparison: the required speed for low Earth orbit is ca. 7.5 km·s-1 = Ma 25.4 in air at high altitudes)
2006-10-03 18:24:14 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Mach speed is around 750 miles per hour.
2006-10-03 18:12:39 · answer #3 · answered by lifescircle 5 · 0⤊ 1⤋
mach is speed of sound in dry air at 25 celcius
2006-10-03 18:09:46 · answer #4 · answered by a 1 · 0⤊ 1⤋
A very poor-working razor. Or maybe they were called Mach 4's... ow well.
2006-10-03 18:07:50 · answer #5 · answered by Anonymous · 0⤊ 0⤋
"mach" speed is the speed of sound
2006-10-03 18:06:08 · answer #6 · answered by doubletap_downzero 3 · 0⤊ 0⤋
Speed of sound at 25 degrees Celcius.
2006-10-03 18:29:13 · answer #7 · answered by msi_cord 7 · 0⤊ 0⤋
Speed of sound- 1130ft/sec.
2006-10-03 18:12:13 · answer #8 · answered by Anonymous · 0⤊ 1⤋
speed of sound at any given airpressure
2006-10-03 18:07:52 · answer #9 · answered by Anonymous · 0⤊ 0⤋