It's 2015 and you aren't even close to owning a Spaceship

Are you seriously suggesting that continuum mechanics says that a gas under pressure does not exert a force on its containing vessel?

Nope.

And you know that.

It says that the 'rebounding billiard ball' molecules schtick mainframes needs for the terrible analogy he's attempting to foist on us is inapplicable.

Free expansion says that when the system reaches equilibrium, the total work done is zero.

Thanks!

Good luck with a 'shpayze-shipp' that does zero work.

Are we done now?

Or can I expect more visits from the BJ1234/luckyfred goon-squad?

Quote from: markjo on November 25, 2015, 10:19:27 PM

Are you seriously suggesting that continuum mechanics says that a gas under pressure does not exert a force on its containing vessel?

Nope.

And you know that.

It says that the 'rebounding billiard ball' molecules schtick mainframes needs for the terrible analogy he's attempting to foist on us is inapplicable.

Quote from: markjo on November 25, 2015, 10:19:27 PM

Free expansion says that when the system reaches equilibrium, the total work done is zero.

Thanks!

Good luck with a 'shpayze-shipp' that does zero work.

Are we done now?

Or can I expect more visits from the BJ1234/luckyfred goon-squad?

It is very apparent that you don't understand what continuum mechanics is. It is a method of simplifying reality in order to make modelling systems easier. Otherwise you have to start solving equations dealing with collections of particles and intermolecular forces. Continuum mechanics approximates by removing the need for the individual calculations. However in doing this it sacrifices accuracy.

A model describing individual particles is incredibly difficult to resolve but it describes what is actually happening. Continuum mechanics gives a best estimate but is far simpler to solve.

The upshot of this is that you cannot ignore an argument that explains how systems work by showing how individual particles behave.

It is very apparent that you don't understand what continuum mechanics is.

It is even more apparent, that, despite what Fluid Mechanics & the continuum assumption tell us, you do not wish to give up on your 'bouncing billiard balls in a tin can' terrible analogy.

Do I really need to fetch all the posts that prove you know nothing about basic physics again?

Besides, markjo has already said this, so the 'debate' would appear to be over:

Free expansion says that when the system reaches equilibrium, the total work done is zero.

A rocket that does zero work?

That'll get you to teh munn!

It's continuum ASSUMPTION, u assume is that way to simplify math, but at very low pressure that assumption is not more true and u don't apply conventional fluid dynamics.

Cindy come on, invent something new, is getting repetitive. A little more effort would be appreciated

Quote from: markjo on November 25, 2015, 10:19:27 PM

Free expansion says that when the system reaches equilibrium, the total work done is zero.

A rocket that does zero work?

That isn't what I said.  First of all, the total of the positive work and negative work add up to zero.  Yes, work is a vector quantity so there is really such a thing as negative work.

Secondly, the total is zero when the system reaches equilibrium.  A rocket that is constantly ejecting large quantities of gas is not at equilibrium (remember that pressure gradient that you love to shitspam about?), therefore the total work being done is not yet zero.

  A rocket that is constantly ejecting large quantities of gas is not at equilibrium, therefore the total work being done is not yet zero.

Think about what you just wrote...

Quote from: markjo on November 26, 2015, 06:19:53 AM

  A rocket that is constantly ejecting large quantities of gas is not at equilibrium, therefore the total work being done is not yet zero.

Think about what you just wrote...

Seems about right to me....

Seems about right to me....

Unsurprising.
 
Everyone else but minions, please read this:

Free expansion says that when the system reaches equilibrium, the total work done is zero.

Then this:

  A rocket that is constantly ejecting large quantities of gas is not at equilibrium, therefore the total work being done is not yet zero.

Then have a think about it...

yet again, in which universe a rocket nozzle is an INSULATED CHAMBER?

cindy, stop butchering physics with ideaous assumptions that have nothing to do with reality.

stick to REAL physics...

but wait... sticking to real physics what u claim is wrong.

oh in that case keep on ignoring REAL physics and continue with the lecture about Cindy's own physics and trolling, u're doing a great job

Sorry, luckyfred/tomfi; I do not speak Gibberish.

Now; read this:

Free expansion says that when the system reaches equilibrium, the total work done is zero.

Then this:

  A rocket that is constantly ejecting large quantities of gas is not at equilibrium, therefore the total work being done is not yet zero.

Then have a think about it...

Can you see what he did there?

yet again, free expansion has nothing to do with rocket propulsion.
 u don't have a closed insulated chamber that suddenly opens into vaccum, u have a FLOW of gass from the combustion chamber.

u don't know what to invent next to defend your claims, do u...Cindy/troll?

free expansion has nothing to do with rocket propulsion.

So; free expansion of GAS in a VACUUM has nothing to do with how GAS powered rockets propel in the VACUUM of 'space'?

LOL!!!

You should probably tell markjo that...

Please read this:

Free expansion says that when the system reaches equilibrium, the total work done is zero.

Then this:

  A rocket that is constantly ejecting large quantities of gas is not at equilibrium, therefore the total work being done is not yet zero.

Then have a think about it...

Can you see what he did there?

free expansion initialia condition: gas in a thermally insulated closed container.

cindy in which universe those conditions resemble the one in a rocket nozzle?

a little more effort trolling cindy

free expansion initialia condition: gas in a thermally insulated closed container.

Rocket fuel initial condition: also gas in a thermally insulated container.

A little more effort thinking, tomfi.

But enough of your buffonish derailing; read this:

Free expansion says that when the system reaches equilibrium, the total work done is zero.

Then this:

  A rocket that is constantly ejecting large quantities of gas is not at equilibrium, therefore the total work being done is not yet zero.

Then have a think about it...

Can you see what he did there?

Quote from: luckyfred on November 27, 2015, 03:54:14 AM

free expansion initialia condition: gas in a thermally insulated closed container.

Rocket fuel initial condition: also gas in a thermally insulated container.

A little more effort thinking, tomfi.

But enough of your buffonish derailing; read this:

Quote from: markjo on November 25, 2015, 10:19:27 PM

Free expansion says that when the system reaches equilibrium, the total work done is zero.

Then this:

Quote from: markjo on November 26, 2015, 06:19:53 AM

  A rocket that is constantly ejecting large quantities of gas is not at equilibrium, therefore the total work being done is not yet zero.

Then have a think about it...

Can you see what he did there?

A working rocket is expelling mass and energy to an outside environment. It is not an insulated closed chamber. Free expansion is NOT an applicable process.

really?
since when there is not heat transfer between gas and combustion chamber/nozzle?

if this is the case u're claims about the melting of the nozzle are wrong.

so cindy, decide, on which one u're wrong?

It is not an insulated closed chamber.

Its fuel tank is.

Which is what I was referring to; please learn to read.

Free expansion is NOT an applicable process.

Okay; let's get this straight; does a rocket in 'space' work by introducing a Gas into a Vacuum?

oh look, u've ignored the part in which i point out u're fails....

cindy, u're so bad at trolling....

ps fuel in  fuel tanks is liquid, not yet a gas

Quote from: Mainframes on November 27, 2015, 04:16:01 AM

It is not an insulated closed chamber.

Its fuel tank is.

Which is what I was referring to; please learn to read.

Quote from: Mainframes on November 27, 2015, 04:16:01 AM

Free expansion is NOT an applicable process.

Okay; let's get this straight; does a rocket in 'space' work by introducing a Gas into a Vacuum?

Correct, the fuel tank is a closed chamber UNTIL they open the valves and start pumping fuel out. Either way the fuel tanks aren't propelling the rocket.

Plus the combustion chamber is most definitely not a closed chamber.

Pathetic argument PooPoo Logbrain. Try harder and at least challenge us with some decent physics and engineering challenges

Looks like you're becoming fluent in Gibberish too, Walt.

Plus, the way you refer to 'us' in your last sentence is particularly LOL!!!

Lastly, of course, neither of you answered my simple question: Does a rocket in 'space' work by introducing a Gas into a Vacuum?

How come i have to answer u and u almost never answer me Cindy?

If the combustion chamber is thermally insulated why u claimed it will melt?

LOL!!!

Does a rocket in 'space' work by introducing a Gas into a Vacuum?

Lol!!!!
Is the combustion chamber insulated yet u claim it will melt?

Ps stick to the physics u can butcher Cindy!!
Thermodynamics is definitely not your thing

More derailing & Gibberish...

Does a rocket in 'space' work by introducing a Gas into a Vacuum?

Simple question.

ahahahaahahahah yeah sure....

since i asked first i think i should be answer first.
if combustion chamber is insulated, how come u claimed it would melt?
answer my question and i'll have the same courtesy and i'll answer yours

stop butchering physics

u can butcher

LOL!!!

Do you & 'frenat' have the same English tutor?

since i asked first

Incorrect.

Now; Does a rocket in 'space' work by introducing a Gas into a Vacuum?

Simple question.

Okay; let's get this straight; does a rocket in 'space' work by introducing a Gas into a Vacuum?

really?
since when there is not heat transfer between gas and combustion chamber/nozzle?

if this is the case u're claims about the melting of the nozzle are wrong.

so cindy, decide, on which one u're wrong?

cindy..look at the time, seems like i beat u for 4 minutes.
i've asked first.
 i'm waiting my answer

*Yawn!*

Seems luckyfred has been assigned to specifically turn this entire thread to shit, by asking me irrelevant questions that have either already been answered or that refer to statements I never made...

So I'll ignore his Gibberish until he does something else funny, like start using the same words as 'frenat', or answer repeatedly to his sock-puppet's name, again...

Now; read this:

Free expansion says that when the system reaches equilibrium, the total work done is zero.

Then this:

  A rocket that is constantly ejecting large quantities of gas is not at equilibrium, therefore the total work being done is not yet zero.

Then have a think about it...

Can you see what he did there?

Also: Does a rocket in 'space' work by introducing a Gas into a Vacuum?

Simple question...

ahahahahahahahahahhahahahahahahahahahahhaha

u're so desperate cindy.
u've been calling everyone a liar and then get caught lying yourself.

say goodbye to your credibility.

ps i will point out that that  free expansion requires NO HEAT TRANSFER, which it's quite not the case of rocket combustion chambers

I don't want to lock a 210+ page topic, but it seems to have devolved into a name calling and trolling accusation match.

One last time:

ATTENTION ALL POSTERS:

THIS TOPIC IS CONSTANTLY BEING REPORTED, THUS FILLING UP MY INBOX AND IS QUITE HONESTLY, ANNOYING ME TO NO END.  CLEAN IT UP OR I WILL BE FORCED TO LOCK THIS TOPIC.