2007-08-03 12:56:34 · 5 answers · asked by dude11 2 in Science & Mathematics ➔ Physics
The speed of sound is 769 mph.
According to Wikipedia: http://en.wikipedia.org/wiki/Speed_of_sound
"At sea level, at a temperature of 21 °C (70 °F) and under normal atmospheric conditions, the speed of sound is 344 m/s (1238 km/h, or 769 mph, or 1128 ft/s or 661.5 kt)."
An aircraft going that fast is said to be going at Mach 1, twice as fast is Mach 2, and three times as fast is Mach 3... The space shuttle enters the atmosphere at Mach 8, and has to slow down from there.
The speed of sound does change, slightly, with altitude decreasing since the air density is reduced, but not by a significant value so the value at sea level is the normally accepted value. The change in temperature has a similar effect, when it is warmer the air molecules are moving faster so sound can travel slightly faster. "Humidity has a small, but measurable effect on sound speed. Sound travels slightly (0.1%-0.6%) faster in humid air." (Same article)
In general the speed of sound = The square root of the following fraction; the stiffness of the item divided by its density. For more detail read the Wikipedia Article.
2007-08-03 13:00:39 · answer #1 · answered by Dan S 7 · 0⤊ 0⤋
It was in the X-1 that Chuck Yeager was the first person to break the sound barrier in level flight on October 14, 1947, flying at an altitude of 45,000 ft (13.7 km). The sound barrier was first broken in a vehicle in a sustained way on land in 1948 by a rocket-powered test vehicle at Muroc Air Force Base (now Edwards AFB) in California. It was powered by 6000 pounds of thrust, reaching 1,019 mph.
2007-08-03 13:07:51 · answer #2 · answered by riley2349 1 · 0⤊ 0⤋
The speed of sound is ambient dependent, so cannot give exact numbers for your question. The speed of sound varies with temperature, so taking a sample of 21 °C , under normal atmospheric conditions, the speed of sound is 344 m/s (1238 kmph). So in this case the aircraft needs to exceed this number for breaking the "barrier".
2007-08-03 16:01:48 · answer #3 · answered by ? 6 · 0⤊ 0⤋
Mach 1
2007-08-03 13:28:13 · answer #4 · answered by Tom B 2 · 0⤊ 0⤋
It depends on altitude and temperature, but Mach 1 is about 760mph at sea level.
http://www.google.com/search?&q=speed+of+sound
http://www.google.com/search?&q=speed+of+sound+in+mph
2007-08-03 13:02:08 · answer #5 · answered by Anonymous · 0⤊ 0⤋