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1
Science & Alternative Science / Re: Do rockets push off the air?
« Last post by RonJ on Today at 05:11:22 PM »
I consulted my physics book that I used while pursuing my engineering degree years ago.  It seems that many people back in the 1920s also insisted that a rocket wouldn’t work in a vacuum.  It took a person like Robert Goddard to prove that supposition wrong.  There were many in the popular press of the day that had lots of fun and called him “Moon man”.  He finally put a gun inside an evacuated jar that fired a blank and proved without a doubt that a rocket would work in space.  He also earned lots and lots of US Patents for his ideas.  Eventually the press printed some retractions and apologies when the advancing space program proved repeatedly that rockets can and do work in a vacuum. 
 
The bottom line is that either there are countless physics PHDs who are dead wrong about their knowledge of the conservation of momentum, or rockets do not work in space as claimed and the whole think is a big farce perpetrated on the public worldwide. 
2
Science & Alternative Science / Re: Do rockets push off the air?
« Last post by DuncanDoenitz on Today at 03:25:00 PM »
So, the rifle bullet thing; 

https://www.uu.edu/dept/physics/scienceguys/2002Sept.cfm

Union University uses a machine gun as an example of a closed system. 
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Science & Alternative Science / Re: Do rockets push off the air?
« Last post by Action80 on Today at 01:17:49 PM »
A closed system can lose matter.
No, it cannot.  That's why it's called a closed system.  You're thinking of an open system.  If you don't believe me, then let's ask Professor Google:
 https://letmegooglethat.com/?q=can+a+closed+system+lose+matter

Of course you won't believe the internet either because it uses the word "exchange" in reference to matter entering or leaving a system.  Maybe this video will help:
Jesus, you just will not quit posting continued bullshit in response. Amazing! You have not changed one bit.

A rocket is a closed system.

Once it is on the launchpad and ready to fire, it takes in nothing else from any system external to itself. It does, however, lose matter (i.e., its exhaust gas) to its external environment.

No exchange takes place.



BWHAHAHAHA! In other words, "No, I am not claiming that, but let me restate that claim here in direct response."
*sigh*  Okay, so you don't understand the difference between "with" and "within" either.  Here's a hint: "within" means "inside".  So when I say that objects can force pair within a closed system, I mean that objects can force pair inside a closed system.  Does that help?
No....https://physics.stackexchange.com/questions/419854/why-an-internal-force-cannot-move-a-closed-system-externally
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Science & Alternative Science / Re: Do rockets push off the air?
« Last post by Action80 on Today at 01:05:55 PM »
@Action80.  A system can comprise several entities.  For example the Joule Experiment, which you sometimes quote, comprises a cylinder, a gas, and (depending on the form used) a piston.  All Markjo is suggesting, and which you apparently find derisible, is that some of these components within the sysem can form a force-pair.  The system as a whole is not "acting against itself", but 2 independant entities within the CLOSED system acting against each other.
More cosigning of the gaslighting. Since you guys like this site so much: https://physics.stackexchange.com/questions/419854/why-an-internal-force-cannot-move-a-closed-system-externally

You guys have been claiming over and over again the combusted gas does the work of moving the rocket inside the combustion chamber, which is just pure bullshit.

A closed system cannot form a force with itself.
Whilst I'm here, can I ask what you believe the nature of the "plume" to be?  By that, I mean is it a gas, does it have substance, does it have mass?  Would you agree that it is formed from the exhaust material of the rocket motor?  Would you agree that, as it is constantly being generated by the motor, that it must be dispersing at an equal rate?  Where is it going?
Of course the plume is exhausted gas.  Of course it is being dispersed out the back at a set rate governed by the exhaust nozzle. 

Remember just a day or so ago when you made the asshatted claim that the muzzle blast has nothing to do with the recoil on a rifle, shotgun, etc.? I mean, I cannot believe you made such an obviously stupid claim, but here it is again in all its wonder:
A rifle cartridge is, and remains, a closed system; bullet goes one way, case and rifle go the other.  Force pair.  Muzzle blast irrelevant.   
Aside from being a stupid claim, let's examine what happens when you happen to put a brake on: https://www.silencercentral.com/blog/how-much-does-muzzle-brake-reduce-recoil/#:~:text=A%20muzzle%20brake%20is%20a,the%20muzzle%20behind%20a%20bullet.
If you read that information you will see what happens when you diffuse the escaping gas (i.e., muzzle blast) on the end of the barrel. Recoil is reduced.

When gas is released to vacuum, guess what happens to that gas? Ah, yes...it becomes absolutely diffused! No ability for an opposite reaction to occur.

Finally, and this is not part of the debate though it's something another couple of people have mentioned; I've no idea of your education level, nor indeed of any of the correspondents on this thread with the possible exception of RonJ who, like myself, says he is a Licensed Aircraft Maintenance Technician.  What I believe, however, is that everyone debating with you is expressing genuinely held opinions.
When the opinion is baseless and without merit, I do not care. I will call it bullshit and state very clearly why it is bullshit. 
Some people may have misunderstood what they have learnt, and everyone seems to have misread what you have written, to the extent that we talk BS, make false claims, lie, strawman and gaslight.  You, on the other hand, are a paragon of truth, despite making repeated claims about the voracity of the "plume" thing, and how it is widely accepted by jet engine manufacturers and your nephew (though entirely without any citations to that effect).   

Without exception I, and the other correspondents, have treated you with utmost respect.  Like a closed system, it would be nice if this were recipricated.
I guess "treating others with respect," must entail making false claims about how jets and rockets, and rifles accomplish motion and experience recoil.
I wonder if the disrespect and aggression shown in your replies is founded in a lack of confidence in your stated opinions.
Calling out obvious bullshit, lying, and gaslighting is absolutely, totally, 100 percent ! ! !, respectful behavior.

I do not care whether you like it or not.
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Arts & Entertainment / Re: Now Playing (the Video Game Version)
« Last post by Vongeo on Today at 04:41:48 AM »
Xbox game pass has cloud gaming so I'm playing Viva pinata but I'm mostly just clicking my second monitor and accidentally quiting my games
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Flat Earth Investigations / Re: Arctic Flights
« Last post by Vongeo on Today at 03:02:56 AM »
Is it accessible to the public?
  You will,of course, have to comply with the entry regulations of whichever country you decide to embark from.
What's your definition of not accessible by the public?
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Science & Alternative Science / Re: Do rockets push off the air?
« Last post by markjo on Today at 12:59:08 AM »
A closed system can lose matter.
No, it cannot.  That's why it's called a closed system.  You're thinking of an open system.  If you don't believe me, then let's ask Professor Google:
 https://letmegooglethat.com/?q=can+a+closed+system+lose+matter

Of course you won't believe the internet either because it uses the word "exchange" in reference to matter entering or leaving a system.  Maybe this video will help:



BWHAHAHAHA! In other words, "No, I am not claiming that, but let me restate that claim here in direct response."
*sigh*  Okay, so you don't understand the difference between "with" and "within" either.  Here's a hint: "within" means "inside".  So when I say that objects can force pair within a closed system, I mean that objects can force pair inside a closed system.  Does that help?
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Science & Alternative Science / Re: Do rockets push off the air?
« Last post by DuncanDoenitz on December 10, 2023, 11:59:57 PM »
@Action80.  A system can comprise several entities.  For example the Joule Experiment, which you sometimes quote, comprises a cylinder, a gas, and (depending on the form used) a piston.  All Markjo is suggesting, and which you apparently find derisible, is that some of these components within the sysem can form a force-pair.  The system as a whole is not "acting against itself", but 2 independant entities within the CLOSED system acting against each other.   

Whilst I'm here, can I ask what you believe the nature of the "plume" to be?  By that, I mean is it a gas, does it have substance, does it have mass?  Would you agree that it is formed from the exhaust material of the rocket motor?  Would you agree that, as it is constantly being generated by the motor, that it must be dispersing at an equal rate?  Where is it going? 

Finally, and this is not part of the debate though it's something another couple of people have mentioned; I've no idea of your education level, nor indeed of any of the correspondents on this thread with the possible exception of RonJ who, like myself, says he is a Licensed Aircraft Maintenance Technician.  What I believe, however, is that everyone debating with you is expressing genuinely held opinions.  Some people may have misunderstood what they have learnt, and everyone seems to have misread what you have written, to the extent that we talk BS, make false claims, lie, strawman and gaslight.  You, on the other hand, are a paragon of truth, despite making repeated claims about the voracity of the "plume" thing, and how it is widely accepted by jet engine manufacturers and your nephew (though entirely without any citations to that effect).  I wonder if the disrespect and aggression shown in your replies is founded in a lack of confidence in your stated opinions. 

Without exception I, and the other correspondents, have treated you with utmost respect.  Like a closed system, it would be nice if this were recipricated. 

9
Science & Alternative Science / Re: Do rockets push off the air?
« Last post by Action80 on December 10, 2023, 08:36:13 PM »
If we were using the word "exchange" in its everyday usage, then you might be correct.  However, we are (or at least I am) using it in the context of its scientific definition, which does not necessarily imply a 2 way trade.

Either way, you're getting hung up on semantics more than the real point: a closed system, by any scientific definition, does not gain or lose matter.  That's why it's called "closed".
Exchange means exactly that. Exchange. A closed system can lose matter.
You are lying and gaslighting. You cannot even comprehend the sources you provide to support your bankrupt position, so providing additional sources would be foolish.
So I'm just supposed to take your word for it?  ::)
Doesn't matter to me whether you take my word for it or not.

You have been called out for it by the moderation here at this site, numerous times, being relegated to Purgatory for an extended period for exactly that.

You are claiming that a closed system can form a force pair with itself, ffs!
No, I am not claiming that.  I am claiming that objects within a closed system can, and must, force pair with each other in order to conserve momentum.  I am claiming that the rocket engine and the exhaust are two of the many objects that make up a closed system rocket and form a force pair that allows the exhaust to accelerate in one direction and the rest of the rocket to accelerate in the opposite direction.
BWHAHAHAHA! In other words, "No, I am not claiming that, but let me restate that claim here in direct response."

GTFO...
10
Science & Alternative Science / Re: Do rockets push off the air?
« Last post by Dr Van Nostrand on December 10, 2023, 07:24:15 PM »
OK.. Let's try this thought experiment...

There's this dude floating naked in weightless vacuum. He's curled up holding his knees in his arms, floating there, and he has a forceful blast of diarrhea. The particles of fecal matter would give his rectum something to push against with no surrounding atmosphere.
The diarrhea would easily shoot out with forward moment and impinge some momentum to the guy's ass, moving him ever so slightly forward.  In fact, if the blast of diarrhea had enough force and volume, it could act as a directional thruster, like on an orbital satellite.

Even if you want to insist that no movement occurred, imagine that you are in a microscopic submarine riding in the dude's colon when he blasted out the diarrhea. Your tiny sub would become a space ship and ride on a wave of diarrhea at sub-relativistic speeds to reach the next star system in 100,000 years.

This is basic science.