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

Quote from: Papa Legba on June 21, 2015, 04:59:37 PM

Sokarul: stop trolling & learn about Free Expansion of gas in a vacuum.

Oh - & LOL!!!

Learn what a nozzle is.
Also
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Quote from: sceptimatic on June 21, 2015, 04:57:06 PM

Quote from: sokarul on June 21, 2015, 04:51:40 PM

Actually is provides a force, Newton agrees. Did you know you can run power tools of air compressors? And you say escaping gas does nothing.

I'm trying to pretend you never said this. 

So power tools run off of air compressors are fake?

No they're not fake.I'm just laughing at you using them as some kind of proof about your silly space rockets working. 

Quote from: sokarul on June 21, 2015, 05:09:11 PM

Quote from: Papa Legba on June 21, 2015, 04:59:37 PM

Sokarul: stop trolling & learn about Free Expansion of gas in a vacuum.

Oh - & LOL!!!

Learn what a nozzle is.
Also
" class="bbc_link" target="_blank" rel="noopener noreferrer">

Quote from: sceptimatic on June 21, 2015, 04:57:06 PM

Quote from: sokarul on June 21, 2015, 04:51:40 PM

Actually is provides a force, Newton agrees. Did you know you can run power tools of air compressors? And you say escaping gas does nothing.

I'm trying to pretend you never said this. 

So power tools run off of air compressors are fake?

No they're not fake.I'm just laughing at you using them as some kind of proof about your silly space rockets working. 

You never could read could you? He said escaping gas did nothing, I showed that it did. Reading comprehension is hard isn't it. Maybe you should go back to the first grade and start over.

Bijane: earlier in this thread you were all stating that the exhaust played no part in the thrust of a rocket & that the work was all done in the combustion chamber.

Yet now the exhaust has become somehow vital to the rocket's functioning; can you really not see the hypocrisy & lack of logic in your position?

NASA claim that both the forces described by Newton's 3rd are created on the rocket alone; this is indisputable, bijane.

& I have proved that this claim can result in no motion; ergo, NASA are wrong.

Simply denying this FACT will not make it untrue.

Really - what is wrong with you, bijane? Your behaviour is genuinely disturbing...

P.s. sokarul; I said escaping gas did nothing IN A VACUUM. This a scientific fact  - so I wouldn't expect you to understand it.

Quote from: sceptimatic on June 21, 2015, 05:06:38 PM

Don't ever be under the impression that crunching numbers and equations makes people geniuses. A genius is a person who can take complicated things and actually dumb them down to a level that anyone can understand.

Sure, great. Except they also need to understand those things when they're complicated, in order to interpret. So, if you're a genius as you've claimed, try reading.

Quote

This is more like it. You see, it's as simple as that. the problem is, you seem scared to actually state what exactly does happen to make this rocket move. You simply mention rocket and fuel. We already know this. What we want to know, is how it works by your model. Explain what happens and why, for this rocket to move.
We've explained our side and you reject it, so explain your side.

What are you asking for? The details of the reaction that make the exhaust come out? Why is that relevant? You seem to just be wasting time. I don't think you can be asking for that, because it doesn't matter: we know the exhaust comes out of the rocket, by observation alone.
So, given that the moves out in one direction, I literally did just explain how it works. So, we're done.

If you forgot:

Quote

A pair of objects are stationary. If one moves, there must be an equal and opposite reaction on the other. In this case, those objects are rocket and fuel. They start off stationary: then the fuel exhaust is forced out, so thre must be an action in the opposite direction on the rocket.

You are scared stiff of explaining how your rocket works. You keep mentioning exhaust but you've already said time and again that the exhaust isn't what propels the rocket, so why not explain how the rocket is propelled by simply telling it as basic as possible without using bullshit equations.

Merely saying conservation of momentum and action/reaction inside the rocket is not telling the full story. Tell that story of how it manages to propel that rocket into space whilst explaining that the exhaust is simply a mild dry fart in the underpants that nobody notices because it's just so insignificant.

You are scared stiff of explaining how your rocket works. You keep mentioning exhaust but you've already said time and again that the exhaust isn't what propels the rocket, so why not explain how the rocket is propelled by simply telling it as basic as possible without using bullshit equations.

You do realize that not thinking doesn't translate to me not answering, right?
The exhaust is an effect. We know that, if it exists, there must be a force in the opposite direction. That is a fact, that is all that is needed to establish that a rocket works. Anything else is just evasion.

Again, I'm not interested in explaining the intimate details of how the fuel works, especially because you'll just ask me to dumb it down despite the fact you've claimed to be intelligent enough to understand it. Instead, I have just one question, which is all you need to answer. How does the exhaust go in one direction, without a force acting in the opposite direction? Irrespective of a cause, how is that possible?

Quote from: sceptimatic on June 21, 2015, 05:11:43 PM

Quote from: sokarul on June 21, 2015, 05:09:11 PM

Quote from: Papa Legba on June 21, 2015, 04:59:37 PM

Sokarul: stop trolling & learn about Free Expansion of gas in a vacuum.

Oh - & LOL!!!

Learn what a nozzle is.
Also
" class="bbc_link" target="_blank" rel="noopener noreferrer">

Quote from: sceptimatic on June 21, 2015, 04:57:06 PM

Quote from: sokarul on June 21, 2015, 04:51:40 PM

Actually is provides a force, Newton agrees. Did you know you can run power tools of air compressors? And you say escaping gas does nothing.

I'm trying to pretend you never said this. 

So power tools run off of air compressors are fake?

No they're not fake.I'm just laughing at you using them as some kind of proof about your silly space rockets working. 

You never could read could you? He said escaping gas did nothing, I showed that it did. Reading comprehension is hard isn't it. Maybe you should go back to the first grade and start over.

Give me a shout when you next use your air compressor tools in space will you. I'll make sure I avoid your space garage because I'd hate to think you were putting my wheel nuts on my space car with your air compressor reliant space tools.
I can just picture me floating along on a space road towards jupiter and my wheels fall off because some cretin believed he'd screwed them on with his air compressor power bolt  driver. 

Now learn to read and comprehend what people really said.

Bijane: you all agreed the exhaust was irrelevant & did nothing earlier.

Why is it such a big deal now?

Is it because you are running out of arguments & getting desperate?

I think so...

Bijane: you all agreed the exhaust was irrelevant & did nothing earlier.

Cause and effect. Let me know when you figure out the difference. The exhaust is an effect. It is not a cause.

Bijane: That's odd; you said that rockets DO push on the atmosphere earlier; but if the exhaust is merely 'an effect' & NOT 'a cause', then by what mechanism does a rocket manage to push on the atmosphere?

Magic?

Bijane: That's odd; you said that rockets DO push on the atmosphere earlier; but if the exhaust is merely 'an effect' & NOT 'a cause', then by what mechanism does a rocket manage to push on the atmosphere?

Magic?

The exhaust is an effect of what causes the rocket's movement, and the cause of the force on the air. You cannot be that stupid. I also repeatedly said that the force acting on the air was a consequence with no relevance to what actually thrust the rocket along, remember? The force in the air too is effect, not cause.

EDIT: clarification.

You have absolutely no idea how a rocket works, do you?

You're just making shit up now... Goodnight.

& LOL!!!

You have absolutely no idea how a rocket works, do you?

Likewise.

Goodnight.

Night! Maybe I'll have the energy to put up with your nonsense in the morning.

Maybe I don't; but I do know how a rocket DOESN'T work: by 'pushing on itself' (lol!).

What's more, I've PROVED it!

So LOL!!!

Maybe I don't; but I do know how a rocket DOESN'T work: by 'pushing on itself' (lol!).

You're absolutely right. You're the only one who's ever proposed that it might.

Your time would be better-spent researching Free Expansion of gas in a vacuum imo, but whatever...

It seems like you're the one who needs to research free expansion a little more.

First of all, Free expansion only applies to a closed system.  Outer space is not a closed system.

Secondly, free expansion applies to an ideal gas that has no mass.  Since rocket exhaust gasses most certainly have mass, free expansion doesn't really apply like you think it does. 

Perhaps you should research how mass flow rate relates to thrust, but whatever...

P.s. sokarul; I said escaping gas did nothing IN A VACUUM. This a scientific fact  - so I wouldn't expect you to understand it.

A change in pressure can perform work, just like a change in temperature.  The work happens as the air escapes.  See air driven power tools. 

You're all clearly arguing with trolls. Why bother anymore? Ignore them and wait for an "FE'r" that at least pretends to be serious, like Jrowe.

Thank you, Ellimist; Sceptimatic & I clearly ARE arguing with trolls!

They don't understand even the simplest laws of physics & lie, evade, ignore & change their stories at the drop of a hat.

Nothing they say makes the slightest sense.

Like markjo here, saying Free Expansion only occurs in a closed system; he is referring to the laboratory experiments which prove free expansion, which use a closed system out of necessity, because how could an infinite vacuum be created in a laboratory?

& claiming that it only works for an Ideal Gas; again, that is from the idealised form of the law necessary to get precisely Zero. In reality, with a real gas, the work done would be as close to zero as makes no difference.

Twisting the facts, see?

The formula for work done by a gas is: Force = Pressure x change in Volume; thus, when the pressure is Zero (as it MUST be in a vacuum), the work done is Zero.

As I said earlier; you can't get Something from Nothing.

Anyone reading the posts on this thread from this weekend will see that mine & scepti's positions have been logical & consistent, whilst our antagonist's have been all over the shop.

Let the neutral reader decide who, precisely, are the trolls.

I would love to see how flat earthers think a molecule can interact with a rocket after it has left the nozzle.  Does it use the force or something?

Trolling again Papa,   if you aren't trolling how about  explaining what you understand about conservation of momentum as it relates to rockets,   you avoided answering so far,  now it's time to put up or shut up.

You never did answer Bijane's question either, you chose to run away and hide instead.

I've explained that c.o.m is irrelevant until we establish that Newton's 3rd applies correctly.

You'd know that if you actually read my posts, Edna.

I've explained that c.o.m is irrelevant until we establish that Newton's 3rd applies correctly.

You'd know that if you actually read my posts, Edna.

Ok,   the exhaust gas expands inside the combustion chamber and then exhausts via the nozzle,   ( please note the expansion takes place inside the combustion chamber, it is not free expansion ) 
The exhaust gas velocity times it's mass is the momentum imparted to the rocket,  since the mass of the rocket is being reduced as the fuel burns we need to use Tsiolkovsky rocket equation.



This answers your first question about Newton's third law.     

PS.   Enough with the Edna jokes,  she is a friend of mine.

I've explained that c.o.m is irrelevant until we establish that Newton's 3rd applies correctly.

So, let's establish why you think it doesn't.
Are the rocket and the fuel always one thing? Well, clearly not: fuel it ejected from the rocket, so it can't be that. Do you have any reasoning you'd care to explain, or just more of your usual evasion?

Like markjo here, saying Free Expansion only occurs in a closed system; he is referring to the laboratory experiments which prove free expansion, which use a closed system out of necessity, because how could an infinite vacuum be created in a laboratory?

Then why don't you provide a reliable source that explains how free expansion works in an open environment?

& claiming that it only works for an Ideal Gas; again, that is from the idealised form of the law necessary to get precisely Zero. In reality, with a real gas, the work done would be as close to zero as makes no difference.

Please show me one free expansion lab experiment that involves a rocket engine or equivalent.

Twisting the facts, see?

Not at all.  Just trying to clarify them.

The formula for work done by a gas is: Force = Pressure x change in Volume; thus, when the pressure is Zero (as it MUST be in a vacuum), the work done is Zero.

Just out of curiosity, how much expansion do you suppose the liquid oxygen and kerosene experience when they're burned in a rocket's combustion chamber?

Anyone reading the posts on this thread from this weekend will see that mine & scepti's positions have been logical & consistent, whilst our antagonist's have been all over the shop.

Yes, you two have been consistently wrong from the beginning.  Now you're trying to grasp at free expansion as if it's relevant. 

That you all try to downplay & ignore the true properties & nature of a vacuum, especially how it would affect any gas introduced to it, is no surprise; NASA should be the undisputed world leaders on this subject, with many thousands of research papers available due to their unique ability to perform experiments in such an extraordinary medium as the practically infinite hard vacuum of 'space'...

Yet they are not; in fact their website barely mentions free expansion, even though they are ideally placed to discover its parameters...

Now why would that be, I wonder?

Anyway; back to Newton's 3rd, as it is the heart of this matter: please explain how both the forces described by Newton's 3rd can be created on the same object & still result in motion?

The simple experiment I described to you last night showed that no motion would be produced.

And let it be noted that this was only one of several simple experiments or examples of easily-verifiable evidence that I have provided in support of my contention that a rocket pushes on an outside mass.

In return, you have provided NO such experiments & evidence for your contention that a rocket 'pushes on itself' (lol!); all you can come up with is the same old tired, easily debunked, 'man-on-skateboard' FALSE ANALOGY multiple times.

Plus a few drawings & youtubes... Oh, & a fan on a boat.

Yet you all seem to think that I am the unreasonable one in this 'debate'.

So go ahead; brainwash - no, sorry - 'educate' me.

Describe exactly how a rocket works, making sure to indicate exactly where the action-reaction pairing occurs.

You can confer first if you like...

LOL!!!

the forces described by Newton's 3rd can be created on the same object & still result in motion?

We're still waiting for what parameters you use to conclude they're the same object.
Are you saying the fuel remains inside the rocket, at the exact same volume, all through the flight?

Would you look at that, another yes or no question for you. Can I expect an answer today? This should really be a simple one for you.

This whole question is very easily settled (no imagination required):

1. Blow up a party balloon to a normal party balloon size.
2. Pinch the "nozzle" with your fingers, keeping the air inside as you do so.
3. Prod the outer skin of the balloon and notice that the balloon is now pressurized.
4a. Release the air slowly and observe what happens to the end opposite the nozzle.
4b. Release the air faster than 4a and observer what happens to the end opposite the nozzle.
4c. Release the air faster than 4b and observer what happens to the end opposite the nozzle.

In case you don't have a party balloon available the following is observed:

4a: the end opposite the nozzle (and the entire balloon) contracts slowly.
4b: the end opposite the nozzle (and the entire balloon) contracts a bit faster than 4a.
4c: the end opposite the nozzle (and the entire balloon) contracts a bit faster than 4b.

Conclusion

No additional force is applied to the opposite end of the nozzle, regardless of the speed of the gas exiting. Instead, the force on the end opposite the nozzle is reduced proportionally to the speed of the gas exiting from the nozzle. Therefore, we can dismiss the notion that the internal gas pushes the rocket along.

Edit: Modified conclusion to read "the internal gas pushes the rocket along."

Nice job of selective quoting, BJ!

Still don't want to talk about that pesky free expansion, or vacuums in general, do you?

Tell me where the action-reaction pairing occurs in a rocket.

That's the crux of the matter, so stop avoiding it.

I've proved that no object can 'push on itself ' (lol!) & produce motion; so what does a rocket push against?

You admit that a rocket CAN push on an outside mass; yet you deny the importance of this FACT.

Okay then; what DOES it push against?

P.s. nicely, legion; if only the cultists could provide such simple experimental proofs of their absurd notions...

That you all try to downplay & ignore the true properties & nature of a vacuum, especially how it would affect any gas introduced to it, is no surprise; NASA should be the undisputed world leaders on this subject, with many thousands of research papers available due to their unique ability to perform experiments in such an extraordinary medium as the practically infinite hard vacuum of 'space'...

Yet they are not; in fact their website barely mentions free expansion, even though they are ideally placed to discover its parameters...

Now why would that be, I wonder?

Because, as I've already said, free expansion isn't relevant to rockets.  Think mass flow rate.

Anyway; back to Newton's 3rd, as it is the heart of this matter: please explain how both the forces described by Newton's 3rd can be created on the same object & still result in motion?

Again, the rocket and the combustion gasses are not the same object. 

The simple experiment I described to you last night showed that no motion would be produced.

A bad analogy doesn't work.  Big surprise.

And let it be noted that this was only one of several simple experiments or examples of easily-verifiable evidence that I have provided in support of my contention that a rocket pushes on an outside mass.

In return, you have provided NO such experiments & evidence for your contention that a rocket 'pushes on itself' (lol!); all you can come up with is the same old tired, easily debunked, 'man-on-skateboard' FALSE ANALOGY multiple times.

We don't have any experiments of a rocket pushing against itself because that isn't what we're claiming is happening.  Don't you ever get tired of making these stupid straw men?

Describe exactly how a rocket works, making sure to indicate exactly where the action-reaction pairing occurs.

We have, countless times.  After a while, the fact that you can't seem to get becomes your problem, not ours.

Conclusion

No additional force is applied to the opposite end of the nozzle, regardless of the speed of the gas exiting. Instead, the force on the end opposite the nozzle is reduced proportionally to the speed of the gas exiting from the nozzle. Therefore, we can dismiss the notion that the internal gas pushes the rocket along.

Edit: Modified conclusion to read "the internal gas pushes the rocket along."

Legion, it isn't a matter of an additional force being applied to the end opposite the nozzle.  It's a matter of the force at the opposite end of the nozzle not being balanced by the open nozzle end.