1

Science & Alternative Science / Re: Do rockets push off the air?

« on: Today at 06:27:28 PM »

Absolutely gaslighting again.

An exchange is where 1 system provides something to a 2nd system in exchange for something the 2nd system provided to system 1.

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".

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? 

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.

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Science & Alternative Science / Re: Do rockets push off the air?

« on: Today at 05:47:09 PM »

If there is no force pair, then what causes the exhaust to accelerate in one direction and the rocket to accelerate in the other?

Have you read the thread?

Sorry, but an exhaust plume force pairing with the ever thinning atmoplane doesn't cut it.  That is unless you can show the math that proves that an ever thinning atmpolane can form a force pair that is sufficient to propel several hundred tons of rocket upwards.

Losing sight of the word, "exchange".

Not at all. 

Two types of exchange can occur between system and surroundings: (1) energy exchange (heat, work, friction, radiation, etc.) and (2) matter exchange (movement of molecules across the boundary of the system and surroundings).

You're the one who seems to be losing sight of the word "closed" as it applies to thermodynamic systems.

Based on the types of exchange which take place or don't take place, we will define three types of systems:

    isolated systems: no exchange of matter or energy
    closed systems: no exchange of matter but some exchange of energy
    open systems: exchange of both matter and energy

Have you read the thread?

Have you read a physics text book?

Or are you just going to continue your lying, gaslighting ways?

No lying or gaslighting.  Just trying to educate you.  Some words can have a somewhat different meaning in physics than in everyday usage, so I suppose that I can see how you might not be able to tell the difference.

But if you insist that I'm lying, then please provide a credible source that disagrees with me and agrees with you.  Citing yourself doesn't count.

3

Science & Alternative Science / Re: Do rockets push off the air?

« on: Today at 12:30:27 AM »

So there is a force pair between the rocket and the exhaust gas?  Glad we have that settled.

The exhaust gas (plume) is part of the rocket. A single system cannot form a force pair with itself.

If there is no force pair, then what causes the exhaust to accelerate in one direction and the rocket to accelerate in the other?

I think you are blind to the meaning of the word "exchange."

A rocket does not exchange matter with its surroundings, It only gives matter (i.e., exhaust) to its surroundings. It takes in nothing from its surroundings.

A closed system cannot form a force pair with itself.

And you are blind to the meaning of the word "closed". 

Propellant from outside the rocket loaded into it and then forcibly ejected back outside of it.

A closed system does not take in matter from from outside of itself or eject matter to the outside of itself.  That would be an open system.

If you must insist that a rocket is a closed system, then you must understand that the rocket engine and the resulting exhaust gasses are 2 elements within that closed system that can and must force pair because momentum must be conserved in a closed system. 

It isn't a case of the closed system force pairing with itself.  It's a case of the force pair happening within the closed system.  A very significant difference that you don't seem to grasp.

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Arts & Entertainment / Re: Now Playing

« on: December 09, 2023, 11:11:52 PM »

A little late, but R.I.P. Myles Goodwyn.

5

Philosophy, Religion & Society / Re: President Joe Biden

« on: December 09, 2023, 09:33:28 PM »

Why should Congress put Biden through the wringer for something they refused to hold Trump accountable for?

Because Trump is above the law and Biden isn't.  Why else?

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Science & Alternative Science / Re: Do rockets push off the air?

« on: December 09, 2023, 08:25:42 PM »

A rocket is a closed system. I haven't ignored the conservation of momentum.

You do understand that a closed system can have more than one component, don't you?

Relevance? 

The rocket engine is one component and the propellant is another.

Oh, here is the relevance. A statement of something very obvious. Thank you.

If the propellant is burnt in the combustion chamber causing the exhaust gasses to be accelerated out the back, then what balances the momentum of that accelerated exhaust gas?

Exhaust gas goes one direction, rocket goes the other direction.

So there is a force pair between the rocket and the exhaust gas?  Glad we have that settled.

Jesus, how many times must this be written?

Until we get this next bit straightened out.

A closed system cannot form a force pair internal to itself. In the case of both jets and rockets, that force pair can only be formed with an outside environment that has measurable air pressure.

Okay, I think that I see the source of your confusion.  You don't seem to understand what "closed system" means.  A closed system does not exchange matter with its surroundings.  That's why it's called a CLOSED system. 

You already agreed that closed systems can have more than one component, therefore you must also agree that force pairs can (and indeed, must) exist within a closed system so that momentum is conserved.

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Science & Alternative Science / Re: Do rockets push off the air?

« on: December 09, 2023, 05:34:01 PM »

A rocket is a closed system. I haven't ignored the conservation of momentum.

You do understand that a closed system can have more than one component, don't you?  The rocket engine is one component and the propellant is another.  If the propellant is burnt in the combustion chamber causing the exhaust gasses to be accelerated out the back, then what balances the momentum of that accelerated exhaust gas?

Just what is the "relevant work " of a rocket?

It is the exhaust plume (i.e., mass ejected, at an accelerated rate) going in one direction causing the rocket or jet to go in the opposite direction.

What causes the exhaust plume to accelerate in one direction?  Or do exhaust gasses not require a force pair to accelerate?

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Science & Alternative Science / Re: Do rockets push off the air?

« on: December 09, 2023, 01:26:30 AM »

The exhausted gas is part of the rocket. A rocket is a closed system.

If you want to consider a rocket to be a closed system, then you must not ignore conservation of momentum.  If the exhaust is being accelerated one way, then the rest of the rocket must be accelerated the opposite way in order for momentum to be conserved.  That is, unless you think that accelerating rocket exhaust doesn't exhibit momentum.

Gas, when released to vacuum, performs 0 work.

True, but irrelevant.  All of the relevant work is done inside the rocket engine, before the exhaust is released into the vacuum.

9

Science & Alternative Science / Re: Do rockets push off the air?

« on: December 07, 2023, 11:37:02 PM »

What "angular momentum?"

I’m not talking about rockets in this case. I’m asking simply if you believe the concept of conservation of angular momentum to be correct. Out of curiosity. Literally a yes or no question.

You should have asked about conservation of momentum in general rather than angular momentum in particular.

I'm still curious about what quality of an exhaust plume allows it to push off a medium less dense than itself.

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Science & Alternative Science / Re: Do rockets push off the air?

« on: December 07, 2023, 03:42:19 AM »

I've no idea what the "plume" is that Action80 refers to in respect of a gas turbine engine. 

My guess is that he's referring to this:

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Science & Alternative Science / Re: Do rockets push off the air?

« on: December 06, 2023, 11:10:46 PM »

Jet engines do the same.
“After compression it was heated, augmented by additional burning fuel(reported in the press to be kerosene), and finally discharged from the aft vent in a monstrous jet of energy pushing against the atmosphere.”

The atmoplane doesn't seem very solid to me.  Wouldn't that "monstrous jet of energy" just push the atmoplane out of its way, especially at higher altitudes where the air is much thinner?

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Philosophy, Religion & Society / Re: President Joe Biden

« on: December 06, 2023, 10:20:21 PM »

Even under the scenario that Hunter Biden was collecting money under the guise of providing access to political power, but was really scamming the people paying him, how can you maintain that this shouldn't be investigated by Congress? Why are you guys crying that this should not be investigated?

Hey, it's not as if Joe Biden appointed Hunter as a presidential advisor while Hunter was making truckloads of money from outside business interests.
https://www.citizensforethics.org/reports-investigations/crew-investigations/jared-and-ivanka-made-up-to-640-million-in-the-white-house/

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Arts & Entertainment / Re: Now Playing

« on: December 06, 2023, 09:48:53 PM »

The anti-work song:

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Arts & Entertainment / Re: Now Playing

« on: December 06, 2023, 02:07:15 AM »

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Arts & Entertainment / Re: Now Playing

« on: December 04, 2023, 02:45:25 AM »

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Philosophy, Religion & Society / Re: Trump

« on: December 04, 2023, 02:12:35 AM »

https://www.bbc.co.uk/news/world-us-canada-67598948

Are you MAGA lot sick of all the winning yet?

Ironic comment from you since Trump is now winning the polls.

Too bad that winning polls doesn't necessarily translate into winning elections.  Or criminal trials.

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Arts & Entertainment / Re: Now Playing

« on: December 01, 2023, 12:22:27 AM »

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Philosophy, Religion & Society / Re: President Joe Biden

« on: November 30, 2023, 10:30:29 PM »

The punchline is that most Republicans can't explain specifically any evidence supporting their narrative. After years of searching, all we keep hearing is 'foreign money from U.S. adversaries' without a molecule of proof. They know how stupid they're going to look when they put Hunter on the stand and it becomes obvious that they have no real evidence.

Nah.  They'll probably just double down and accuse Hunter of lying and charge him with obstruction or something stupid like that,

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Philosophy, Religion & Society / Re: Trump

« on: November 27, 2023, 03:39:52 AM »

Again, you guys are arguing for possibility instead of probability, purely as excuse making for the lack of evidence in this case.

Lack of evidence?  Obviously the jury thought that there was enough evidence to find Trump liable for sexual assault.  That isn't a trivial charge.  If it were a criminal trial, he would likely be doing jail time and then be required to register as a sex offender.  Is that really the kind of man you want back in the White House?

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Philosophy, Religion & Society / Re: Trump

« on: November 27, 2023, 02:12:15 AM »

Yes, it is possible that a woman does not scream in a department store when she is raped against her will. However, it is improbable.

It's quite a lot more probable than you think.  Or don't you think that being paralyzed by fear is a thing?

The series of explanations presented are pure excuse making, which you are explicitly making to explain away and justify a lack of evidence in this case. You pretend that we should be completely on board with believing a series of improbable excuses.

Sure, they're flimsy excuses...   Until you look at the psychology and biology of what happens in the brain when someone is experiencing a highly stressful situation, like being raped.
https://www.washingtonpost.com/news/grade-point/wp/2015/06/23/why-many-rape-victims-dont-fight-or-yell/