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"Perhaps the shock wave travels faster than the speed of sound in air.
I think that is the physics question."
By definition. It's not a shock wave if it travels at the speed of
sound. When the shock wave slows * to Mach one it's sound.
This is a neat picture. Interestingly, the "wake angle" is a function of
http://www.pbs.org/wgbh/nova/barrier/boom/concept3.html
a
* For the std. one Kg TNT explosion (4610 kJ), the range of the blast
(shock) wave is ~ 20 miles. At one mile its speed is ~ 2k m/s and at
ten it's ~ 450 m/s.
bc
Karl Trappe wrote:
Was it Aristotle who said "Answer a question but with a question"?
I think the given answer is to a totally different question. It is
not can the pilot hear what is in the cockpit, but can the pilot hear
his own sonic boom?
Perhaps the shock wave travels faster than the speed of sound in air.
I think that is the physics question.
Karl
At 3:46 PM -0600 11/24/03, Jorge Salazar wrote:
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Wednesday, November 26, 2003
SOUND SPEED
Sound waves move at about 340 meters per second -- about two-tenths of
ormile per second. A listener wonders if you can hear anything when you
travel faster than sound. The answer -- after this on Earth and Sky.
_________________________________________________________
DB: This is Earth and Sky. When we visited the National Air and Space
Museum in Washington D.C., we got this question.
Caitlin Rush: My name's Caitlin Rush, and I'm from State College,
Pennsylvania , and I ask, "When you're traveling at the speed of sound
car.faster can you hear anything?"
JB: Caitlin, the answer is yes. Imagine you're seated in a parked
speakerYou switch on the radio. The car's speakers begin to vibrate. The
thiscone presses against air molecules near the speaker, which push against
neighboring air molecules. Much like firefighters passing a bucket,
thiswave of pressure eventually reaches your ears. Your brain interprets
- orwave of pressure as sound.
DB: Now imagine you attach a pointy nose to your car and add enough
horsepower to break the sound barrier. As you cruise at more than 340
meters per second -- that's more than two-tenths of a mile per second -
radio.faster than the speed of sound -- you reach over and switch on the
hearYour car -- and you -- and all the air molecules around you -- are
traveling that fast. So the sound wave pushes away from the vibrating
speakers in exactly the same way it did in the parked car, and you can
aircraft!the sound.
JB: And that's good news for pilots and passengers of supersonic
ScienceThanks for your question, Caitlin. And with thanks to the National
Foundation, we're Block and Byrd for Earth and Sky.
http://www.earthsky.com/2003/es031126.html
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