Speed of sound riddle

If I was standing at the centre of plane circling faster than the speed of sound what would I hear?

This question stumped me...can you help?

 

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The air within the plane will have had a force acted upon it by the fuselage of the plane and have been accelerated as the plane was. Inside the cabin, the air will most likely be relatively motionless, thus you'll be able to hear everything as normal. Now if you were on the OUTSIDE of the plane, and had some sort of special body that let you survive that, what you'd hear would be something completely different.... and... unknownst to me.

-AntonK

 

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I think he meant 'plane' as in the mathmatical sense of the word.

 

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No, I don't think I explained it well enough. Say your hovering in mid-air and this F14 is flying in a circle around you. It is flying at Mach 2 (say)...what will I hear? The airplane will keep catching up with its produced noise.

 

The speed of sound is actually rather slow, so depending on how big the circle is, you'll have a noticable different in where you SEE the plane and where you HEAR the plane. But this is true for planes doing less than Mach 2 or even Mach 1 for that matter. If you ever see a jet flying overhead, you'll notice you can often hear the plane a litter farther back from where you actually see it.

In your scenario, if the plane is going fast enough, and depending upon the size of the circle, you could actually I believe have it so that you HEAR the plane exactly opposite side of th circle from where you hear it. That would be a bit jarring for the brain I believe.

-AntonK

 

If the circle was quite small would you not hear multiple sonic booms as the plane keeps hitting its past noise?

Thanks for your time.

 

I don't think it would be a "boom", it would be constant.

 

I think Cato has it right. The shock wave would continually be moving around you making a constant roar.

 

HI NAUGHTY.
NOTE THAT SOUND IS TRANSMITED ONLY BY MOVING AIR.WITH NO AIR THERE'S NO SOUND(IN THE MOON THER'S NO SOUND)THUS IF MOVEMENT IS MADE FASTER THAN THE SPEED OF SOUND, THIS MAKES THE AIR AROUND TO MOVE FASTER AND THUS A SOUND WITH A HIGHER PITCH IS HEARD BECAUSE THE SOUND WAVES CAUSED BY THE RAPID MOVEMENT HAVE SHORTER WAVELENGTHS.AND U KNOW WAVES WITH SHORT WAVELENGHT HAVE HIGHER FREQUENCIES AND HIGH PITCH
ANYOTHER QUESTION

 

I understand sound in a vacuum; and I understand that there will be no doppler effect - so with your explanation, are you saying that we will have a higher-than-normal pitched constant boom if we accept Cato's explanation?

 

The sonic boom is caused by the shockwave formed whe the supersonic object 'punches through' the built-up waves of air in front of it. The shock wave is an abrupt transition between an area of high and low pressure. The doppler effect that NACHMAN mentioned is caused by a compression of sound waves in front of a fast moving object coming towards you but is not applicable here because the plane is remaining at a constant radius from you.

In constant velocity supersonic flight the shock wave will come off the aircraft at an oblique angle like the waves trailing a boat. Picture a boat going around in a circle around you while you float in the middle. There will be a whole bunch of confused noise all around you - a constant roar.

 

By the way, your caps lock key is 1/8th of an inch away from your pinky. Thats how far you would have to move it to stop looking like a complete idiot.