# Question regarding sound

## Main Question or Discussion Point

Suppose there is a passenger jet traveling slightly faster than the speed of sound. There are only two passengers on the jet (excluding the pilots.) One passenger in the seat closest to the back(passenger A) of the plane and one at the seat nearest to the nose(passenger B). If passenger A were to yell to passenger B, would B never hear the yell? If that is true then if B were to yell towards the front of the plane, would A catch up to the the yell?

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Your hypotehis assumes as if the jet is open to air outside...Passenger b can hear the yell since sound waves can be considered to be vibration of the medium

Hi,
I do not agree with .ultimate. I think that sound uttered by passenger A will add to the shock wave created by the passenger himself but will not go further. In the shock wave the sound velocity is higher than in the air outside because the air is hotter.

supposing the outside air temperature is not afffecting things inside the jet(whatever is the shock wave theory), then A & B should be feeling like they are talking in a discussion room! this is because when you say that A hears something being said, it means that the sound vibrations reach A's ears. As the air inside the plane is constantly moving along with the jet body, its like being in a discussion room itself...

russ_watters
Mentor
As long as the plane isn't open to the outside, the air inside is still, so the plane's motion has no effect on the way sound works inside the cabin.

Haven't you guys heard of the Concorde?

I do not think that the question of Orl13 was "where the passengers able to hold a conversation inside the Concorde". If this was the case, the question is uninteresting. I thought the question was about transmission of sound outside the plane and making abstraction of the biological impossibilities. If this poses a problem, you can replace passengers by sound transducers. If I misunderstood, I apologize.

vanesch
Staff Emeritus
Gold Member
Haven't you guys heard of the Concorde?
Wasn't this the reason why the concorde was taken out of the air ?
The hostess couldn't talk to the pilot when they were flying at Mach 2 :rofl: :rofl:

russ_watters
Mentor
I do not think that the question of Orl13 was "where the passengers able to hold a conversation inside the Concorde". If this was the case, the question is uninteresting. I thought the question was about transmission of sound outside the plane and making abstraction of the biological impossibilities. If this poses a problem, you can replace passengers by sound transducers. If I misunderstood, I apologize.
Well, the OP mentions seats, and after that disaster in the '60s, they don't mount seats outside the plane anymore..... :tongue2:

brewnog
Gold Member
Haven't you guys heard of the Concorde?
Evidently not. It's impossible to hear of the Concorde because it's supersonic. People may have seen of the Concorde...

I did heard the Concorde (well, only the shock wave).

russ_watters
Mentor
Evidently not. It's impossible to hear of the Concorde because it's supersonic. People may have seen of the Concorde...
Terrible, terrible joke, brewnog - I expect better from you. :tongue:

I'm sorry, I guess I didn't clarify the question well enough. Actually the concorde is the aircraft that I had in mind when I thought up this question the other day. The two passengers are sitting Inside the jet. Simply, can B hear a yell from A since the jet since the jet is traveling faster than sound?

russ_watters
Mentor
As the joking responses should imply, there isn't anything different between what goes on inside a Concorde than what goes on inside a subsonic jet. People hold normal conversations - no yelling required.