Fall from 24 miles -- terminal velocity?

[Hussar]

And now I know. And that's half the battle.

 

[Someone]

Sorry, guys, but you're misremembering. The speed of sound is *not* strongly related to the density or pressure of the gas. It is strongly dependent on the temperature.

For an ideal gas, the speed of sound c = sqrt(g*k*T/m)

Where:
g (actually gamma) is the adiabatic index - the ratio of specific heats of the gas.
k is the Boltzmann constant
T is the absolute temperature
m is the mass of a single molecule of the gas

Now, most gases are not quite ideal, but air is quite nearly so, and the effects of it being non-ideal are small. The speed of sound changes with altitude because the temperature changes with altitude.

That's right. Actually, the basic speed of sound formula does include density; but when you substitute on it the ideal gas ecuation it gives the result you posted.

Also, despite being inversely porportional to the square root of density is also porportional to the suare root of the bulk modulus, which is the resistance to being compressed. This is quite higher on solids and liquids than gases.

 

[Dannyalcatraz]

For example, the aproximate speed of sound in salt water (for a standard salinity, depth, and temperature), is about 1560 m/s (or just shy of 3,500 mph).

Which is why whales don't need cellphones.

[ame="http://www.youtube.com/watch?v=K0fa_QCu2K0&sns=em"]http://www.youtube.com/watch?v=K0fa_QCu2K0&sns=em[/ame]

"Can you hear me NOW?"

 

[Umbran]

That's right. Actually, the basic speed of sound formula does include density; but when you substitute on it the ideal gas ecuation it gives the result you posted.

Yes, which is to say, it depends on density *and* pressure, in such a way that, for ideal gasses, what actually matters is the temperature and mass of particles.

 

[Scott DeWar]

For example, the aproximate speed of sound in salt water (for a standard salinity, depth, and temperature), is about 1560 m/s (or just shy of 3,500 mph).




*I'm an Avionics Specialist.

and for those who can do simple math like me, that is about 2/3 of a mile per second.

*I was only avionics communications specialist.

 

[El Mahdi]

*I was [an] avionics communications specialist.

Comm/Nav is Cool! Two sides of the same coin.

I cut-trained into Comm/Nav when I worked on 60's due to personnel/qualification shortages. Radars and Radios are Fun!*


*At least until Aircrews start whining about their SatCom!

 

[Scott DeWar]

I worked on F-4s back in the 80's

 

[El Mahdi]

I worked on F-4s back in the 80's

Phantoms are cool! My first were B-52's (H models), and KC-135A's at K.I. Sawyer in the late 80's.

 

[Scott DeWar]

George AFB for me. e's and g' s