Gue Vs Tdi
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cornfed
Mindless lemming
Could you (or someone else) please close the thread before the carcass isNWGratefulDiver:
exhumed again?
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What's to be disappointed ... that I didn't get involved in your little ******-measuring contest? I'm not interested in "impressing" our board's members that way.nova:
For what it's worth, I'm a DAN instructor ... and you haven't a clue what I know or don't know on the subject, because I haven't told you.
I plan to keep it that way.
... Bob (Grateful Diver)
Hey, Bob, are you sure you want to break up this chick fight? I know it's boring but the more time these two stay back here, pulling each others hair and shredding each others panties, the less time they'll have out on the rest of the board.
lamont
Contributor
I know I should just step away here, but...
nova is wrong here, 'nuff said.
oddly enough he's basically correct here. you can also write the ideal gas law as:
PV = NkT
where N is now the count of the nuber of atoms rather than the number of moles (N = n * avogadros). kT is boltzmann's constant times the absolute temperature -- which is a measure of energy. what that equation is stating is that for every molecule of gas you get a contribution of kT from its kinetic energy.
this is actually a much more elegant way to write the equation when you've got the additional background of thermodynamics where integral or half-integral factors of kT's tend to pop up all over the place.
what i've forgotten is why you don't get 3/2 kT for the 3 dimensions of translational kinetic energy that each molecule has -- that can be someone else's homework assignment though...
again, wrong here.
nova:
nova is wrong here, 'nuff said.
oddly enough he's basically correct here. you can also write the ideal gas law as:
PV = NkT
where N is now the count of the nuber of atoms rather than the number of moles (N = n * avogadros). kT is boltzmann's constant times the absolute temperature -- which is a measure of energy. what that equation is stating is that for every molecule of gas you get a contribution of kT from its kinetic energy.
this is actually a much more elegant way to write the equation when you've got the additional background of thermodynamics where integral or half-integral factors of kT's tend to pop up all over the place.
what i've forgotten is why you don't get 3/2 kT for the 3 dimensions of translational kinetic energy that each molecule has -- that can be someone else's homework assignment though...
again, wrong here.
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...
NWGratefulDiver:
In this case, that equine is mummified!
lamont
Contributor
nobody appreciates a good physics problem these days...
so, from basic physical dynamics (good old billiard balls bouncing off the walls of a container) you can arrive at:
P = 2/3 (N/V) (1/2 m <v^2>)
then the equipartition theorem does, in fact, hold:
Ek_x = 1/2 kT
Ek_y = 1/2 kT
Ek_z = 1/2 KT
Ek_tot = 1/2 m <v^2> = 3/2 kT
which leads by substitution to:
P = 2/3 (N/V) (3/2 kT)
which gives us:
PV = NkT
w00t.
for diatomic gases (N2 / O2) you also get for total energy from the equipartition theorem:
E_tot = Ek + rotational + vibrational = 3/2kT + 1/2kT + 1/2kT = 5/2kT
this affects the heat capacity of the gases and makes N2 and O2 at a given temperature contain more energy than He -- or stated otherwise, warming up N2 and O2 to body temperature takes away more energy from the body than He -- which is why He is actually not a cold gas to breathe.
lamont:
so, from basic physical dynamics (good old billiard balls bouncing off the walls of a container) you can arrive at:
P = 2/3 (N/V) (1/2 m <v^2>)
then the equipartition theorem does, in fact, hold:
Ek_x = 1/2 kT
Ek_y = 1/2 kT
Ek_z = 1/2 KT
Ek_tot = 1/2 m <v^2> = 3/2 kT
which leads by substitution to:
P = 2/3 (N/V) (3/2 kT)
which gives us:
PV = NkT
w00t.
for diatomic gases (N2 / O2) you also get for total energy from the equipartition theorem:
E_tot = Ek + rotational + vibrational = 3/2kT + 1/2kT + 1/2kT = 5/2kT
this affects the heat capacity of the gases and makes N2 and O2 at a given temperature contain more energy than He -- or stated otherwise, warming up N2 and O2 to body temperature takes away more energy from the body than He -- which is why He is actually not a cold gas to breathe.
cornfed
Mindless lemming
Just because you answered your own question before giving someone else a chance to doesn't mean we don't appericate it.lamont:
JeffG
Contributor
The breeze coming off the propellers can keep everyone cool as well.cornfed:Just because you answered your own question before giving someone else a chance to doesn't mean we don't appericate it.
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