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Old 19th April 2019, 07:29 AM   #441
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Originally Posted by Belz... View Post
One more indication that he doesn't know anything about the topic, and yet he thinks he's going to overturn the current theories science.
FTFY, I know you really didn't mean to type that Newtonian physics is a theory.
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Old 19th April 2019, 08:00 AM   #442
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Originally Posted by Gingervytes View Post
I donít think space travel exists, but who know what other technology is out there. By they certainly do no go into space with rockets
Gingervytes, I repeat - again:

Iíve personally built (as part of a team), integrated, tested, observed the launch of, and operated spacecraft, including postflight testing. Your claim is observed to be wrong.

Any response?. Or are you going to continue ignoring refutations like this one?

Ya know, if it was me, and I was getting my head handed to me by people who actually do spaceflight for a living, as well as an assortment of educated laymen, I would stop and ask myself if maybe I was wrong, and investigate the criticisms of my claims, because itís more important to me to get it right than to cling to my beliefs on an anonymous Internet forum. How about you? Would you like to learn something?
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Old 19th April 2019, 08:25 AM   #443
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Originally Posted by sts60 View Post
Gingervytes, I repeat - again:

Iíve personally built (as part of a team), integrated, tested, observed the launch of, and operated spacecraft, including postflight testing. Your claim is observed to be wrong.

Any response?. Or are you going to continue ignoring refutations like this one?

Ya know, if it was me, and I was getting my head handed to me by people who actually do spaceflight for a living, as well as an assortment of educated laymen, I would stop and ask myself if maybe I was wrong, and investigate the criticisms of my claims, because itís more important to me to get it right than to cling to my beliefs on an anonymous Internet forum. How about you? Would you like to learn something?
There has been no effort on his part to learn anything, just keep repeating the same nonsense adding a few other BS that knows he knows nothing of physics. All he wants is to continue the posting, so I'm done with this TROLL and I should have stopped several pages ago.
Have fun guys.
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Old 19th April 2019, 08:38 AM   #444
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Originally Posted by bknight View Post
FTFY, I know you really didn't mean to type that Newtonian physics is a theory.
I meant exactly what I wrote.
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Old 19th April 2019, 08:38 AM   #445
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Originally Posted by bknight View Post
Originally Posted by Belz... View Post
One more indication that he doesn't know anything about the topic, and yet he thinks he's going to overturn the current theories science reality.
FTFY, I know you really didn't mean to type that Newtonian physics is a theory.

FTFY
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Old 19th April 2019, 08:47 AM   #446
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Originally Posted by Belz... View Post
One more indication that he doesn't know anything about the topic...
Agreed. He's stumbling over basic first-year principles and completely unfamiliar with simple laws like PV/T = k. His arguments display a confusion between density and pressure, and just flatly deny Newton's third law. He seems to have it stuck in his head that the mechanics involved here work only with fluids. His model deals only with the special case of compressible fluids, which certainly can operate in a system that exhibits conservation of momentum. But he seems to think this now means a compressible fluid is required.

Quote:
...and yet he thinks he's going to overturn the current theories.
Really it's like trying to overturn the entire science of modern biology by repeatedly yelling, "The mitochondria is the firehouse of the cell." He omits the analysis-synthesis process. Well, not entirely. He tried that with the proof at the top of the thread (assuming it's his proof), but in making a substitution that holds under one condition he canceled out a variable thinking that the substitution would hold under all conditions. The synthesis step is wrong.
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Old 19th April 2019, 09:24 AM   #447
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Originally Posted by curious cat View Post
The keyword is "drops".
Better key words would be "letting go." Don't get me wrong; your analysis is correct. But if we choose our words carefully we can aid the analysis.

You let go of the weight. But for gravity, nothing would happen. Your fingers would release hold, but no significant motion would occur. Introduce gravity and the weight falls because it and the Earth attract each other. But for the floor, you would fall too -- attracted in the same way. In fact, you would fall at the same rate. Momentum would thereby be conserved between you and the weight. It is not in this case because the floor constitutes an external force. The momentum-conserving system defined by the Earth and the weight remains the same. The momentum-conserving system defined as the Earth and you remains the same.

Quote:
If he "pushed" the weight down while it was falling to accelerate its descent over 9.81m/s^2, he could achieve a point where he would lift himself from the ground. I don't think anybody is fit enough to achieve this though ;-).
No, but if you were standing on a scale and threw something vigorously at the floor, you would be able to measure a reduction in your weight. There would be upward thrust, but not enough to levitate you.

It's more applicable if you imagine this system sideways. The typical way to illustrate conservation of momentum in a classroom is with two students in office chairs who push off from each other. It's best if you choose two who have significantly different mass. Their final resting places obey the law of conservation of momentum, Newton's third law. And if you have students with advanced enough knowledge, you can show that their combined center of mass remains reasonably unchanged. This is about throwing mass, not "pushing against air" or moving toward zones of lower pressure.

Another common apparatus is to sit on a skateboard and roll away a bowling ball. Both you and the ball move. This has nothing to do with the air in the room. Gingervytes doesn't seem to think throwing solid objects out the back of something would result in thrust. He is wrong. Rockets throw mass. The fact that the mass is in the form of a gas makes absolutely no difference.

In engineering we have whole rooms that function like giant air-hockey tables. We use air cushion principles to "float" very large assemblies on a broad, flat surface and thereby and obtain at least two dimensions of relatively frictionless Newtonia. The measurements and calculations we make there involve only the masses and velocities of the objects, not whether there's air or how much the air affects the results. We're typically dealing there with objects with very high mass and very low velocity, so the effect of the ambient fluid is properly ignored. Yet Newton's third law holds.
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Old 19th April 2019, 09:36 AM   #448
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I was just thinking (a dangerous thing to do at the best of times for me)- that 'technically' wouldn't dropping a weight actually lift you???

You are standing holding a weight, and release it
Now (and this is just my musings) when you release the weight, it and the earth are mutually attracted, the weight will move (a lot) towards the earth, and the earth will move (microscopically) towards the weight
You (standing on the earths surface) would also be 'lifted' by this movement of the earth

So technically you would move (ever so incredibly tiny an amount) in the opposite direction to the direction of the weight's travel

I think this is correct?
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Old 19th April 2019, 09:56 AM   #449
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Originally Posted by sts60 View Post
Iíve personally built (as part of a team)...
I should emphasize that we all work in teams in this industry.

Quote:
Your claim is observed to be wrong.

Any response?. Or are you going to continue ignoring refutations like this one?
Same question from me. Earlier he insinuated one rejoinder, the solipsist one. Since all you can personally say is that you saw the rocket rise into the sky and disappear from sight, nothing you claim past that can be considered an observation. It's taken to some degree on faith. He never actually made that argument, but it's really the only place to go from what he did say.

The argument tries to rewrite our respective roles as just low-level flunkies who really don't have the knowledge that refutes his belief. Sure we did all that, but then some hidden, all-powerful entity took over and just magically gave us all we would need to observe indirectly (e.g., telemetry) in order to believe that what we did actually achieved the intended effect. When I pointed out pre-emptively that this is not how engineering works, he had nothing further to add.

It's one thing to say in public, "Those people over there are lying." It's suitably impersonal and only mildly confrontational. It's another thing to say in public, "You, to whom I'm speaking, are lying." That's perhaps more aggressive than the typical claimant is willing to be. So it's safer just to pretend that people don't exist who are able to directly contradict you with direct observation. Or to pretend, by waving your hands vaguely at YouTube, that you've already "proven" whatever those experts are objecting to, and that they must be too ideologically compromised to acknowledge it.

For conspiracy theorists it's always ultimately about which individuals have the least compromised ideology.
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Old 19th April 2019, 10:43 AM   #450
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Originally Posted by Dabop View Post
I was just thinking (a dangerous thing to do at the best of times for me)- that 'technically' wouldn't dropping a weight actually lift you???

You are standing holding a weight, and release it
Now (and this is just my musings) when you release the weight, it and the earth are mutually attracted, the weight will move (a lot) towards the earth, and the earth will move (microscopically) towards the weight
You (standing on the earths surface) would also be 'lifted' by this movement of the earth

So technically you would move (ever so incredibly tiny an amount) in the opposite direction to the direction of the weight's travel

I think this is correct?
You are technically correct. The best kind of correct!
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Old 19th April 2019, 11:44 AM   #451
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Originally Posted by JayUtah View Post
Same question from me. Earlier he insinuated one rejoinder, the solipsist one. Since all you can personally say is that you saw the rocket rise into the sky and disappear from sight, nothing you claim past that can be considered an observation.
Actually, he claimed that you can see them splash into the ocean, too.

The problem is, he doesn't provide us with HIS explanation of what it's doing between the time it disappears from sight and the time it reappears. As I've pointed out, the explanation for that without invoking space travel is a LOT harder than just simply conceding that it went into space.

BTW, I've actually seen the ISS fly by. It was really cool to watch it pass over head. If that wasn't in outer space, where was it? Just like an airplane but really, really, really high up in the air? Instead of going at 30 000 feet, it is just 1.3 mil?
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Old 19th April 2019, 12:01 PM   #452
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Originally Posted by Gingervytes View Post
What do you mean it doesnít? Do you see smoke expands towards the ground?
No, but it doesn't rise because the pressure is lower above. Anyway, what has this to do with your claim that rockets don't work in vacuum?

Hans
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Old 19th April 2019, 12:04 PM   #453
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Originally Posted by Gingervytes View Post
Hot air rises because temperature makes the pressure go up and this creates a pressure gradient.

http://ww2010.atmos.uiuc.edu/(Gh)/gu.../prs/hght.rxml
Nonsense. Hot air rises because it is lighter than cool air. What has this to do with rockets?

I'm serious here: If you keep doing this, I'll report you for derailing.

Hans
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Old 19th April 2019, 12:05 PM   #454
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Originally Posted by pgwenthold View Post
Actually, he claimed that you can see them splash into the ocean, too.
Thank you; I missed where he claimed that.

Quote:
As I've pointed out, the explanation for that without invoking space travel is a LOT harder than just simply conceding that it went into space.
Yeah.

Quote:
BTW, I've actually seen the ISS fly by.
As have quite a number of people. The optics to see it as an actual assembly of objects and not just a dot of light are well within the means of the middle class to acquire. Consequently it has been viewed directly in its purported form by too many people to simply dismiss.
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Old 19th April 2019, 12:09 PM   #455
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Originally Posted by curious cat View Post
Another person who shouldn't play with guns :-). The explanation goes back to F=m*a. As you are accelerating bigger mass, you get a bigger force. That simple. You may try argue the amount of energy is the same, limited by the size of the charge. Almost right, except in the case of the smaller bullet it gets out of the barrel before all the gunpowder burns. The heavier one gives it more time and the combustion is more complete - meaning more energy to do the job.
In the case of "no bullet at all" a lot (if not most) of the propellant will get out before it burns and the efficiency will be very small. Automatic weapons may not function for that reason - a "blanks attachment" may be needed to solve the problem. Note; in that case all the forces are confined inside the barrel and no outside "support" of some kind is involved.
And how is this relevant for the topic? A gun is optimized to exploit the cartridge charge to propel a bullet, so this is what it does best. If we optimized it differently, as a rocket, that same charge would work best for that.

Hans
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Old 19th April 2019, 12:10 PM   #456
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Originally Posted by RecoveringYuppy View Post
The pressure gradient is also "up", on average, everywhere. Why doesn't the atmosphere leave the planet I wonder.
Because of gravity. Gravity holds it back.

Hans
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Old 19th April 2019, 12:12 PM   #457
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Originally Posted by dasmiller View Post
You are technically correct. The best kind of correct!
Technically and ironically correct, a double-whammy. If the Earth and the weight move closer together, and the person who let loose the weight is standing on a scale, then the Earth and the person are inertially coupled and the lateral acceleration imposed by the Earth moving to meet the weight will result in a greater weight measured on the scale. It will be the sum of the gravitational attraction between the Earth and the person, and the reaction to the acceleration of the Earth toward the weight, as produced in the person.

A related problem occurs in actual rocketry when you model the spacecraft as a Newtonly-connected pile of components that comprises a system of inertially- and mechanically-coupled elements. The various submasses of a rocket are not rigid, but act like individual masses connected semirigidly. Then there is also fuel slosh, the effects of the mass of propellant wallowing around in the tanks. Elon Musk had some difficulty with this in the early Falcons. It's part of the overall problem of dynamic spacecraft control.

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Old 19th April 2019, 12:13 PM   #458
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Originally Posted by curious cat View Post
Gingervytes:
"Lets say a 75kg person lifts a 100kg weight and he drops it from a height. Why doesnít that person get lifted off the ground? Isnít the weight mass?"

The keyword is "drops". The person is not exerting any force on the weight. He is simply letting gravity to do its job. If he "pushed" the weight down while it was falling to accelerate its descent over 9.81m/s^2, he could achieve a point where he would lift himself from the ground. I don't think anybody is fit enough to achieve this though ;-).
Entirely correct. The equal and opposing force is not between the person (or whatever) releasing the weight, it is between Earth and the weight.

Hans
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Old 19th April 2019, 12:14 PM   #459
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Originally Posted by Gingervytes View Post
And in the case of a rocket. Pressure expands due to pressure gradient force and not because the rocket pushes it
Second sentence makes no sense. What were you trying to say?

Hans
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Old 19th April 2019, 12:26 PM   #460
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Originally Posted by JayUtah View Post
The various submasses of a rocket are not rigid, but act like individual masses connected semirigidly. Then there is also fuel slosh, the effects of the mass of propellant wallowing around in the tanks. Elon Musk had some difficulty with this in the early Falcons. It's part of the overall problem of dynamic spacecraft control.
FWIW, I've spent waayyyy too much time modeling the behavior of propellant in spacecraft tanks in 0G, specifically for spacecraft dynamics (as opposed to, say, unporting).
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Old 19th April 2019, 12:32 PM   #461
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Originally Posted by dasmiller View Post
FWIW, I've spent waayyyy too much time modeling the behavior of propellant in spacecraft tanks in 0G, specifically for spacecraft dynamics (as opposed to, say, unporting).
The hundred-million-dollar equivalent of carrying the ice cube tray from the sink to the freezer.
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Old 19th April 2019, 12:53 PM   #462
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Originally Posted by Gingervytes View Post
What do you mean it doesnít? Do you see smoke expands towards the ground?
Originally Posted by Gingervytes View Post
Hot air rises because temperature makes the pressure go up and this creates a pressure gradient.

Originally Posted by MRC_Hans View Post
Nonsense. Hot air rises because it is lighter than cool air. What has this to do with rockets?

I'm serious here: If you keep doing this, I'll report you for derailing.

I particularly like the fact that in consecutive posts heís argued that smoke doesnít expand downwards and proposed a hypothesis that predicts that it does.
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Old 19th April 2019, 01:06 PM   #463
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Is it too late to point out that the reason why a gas wants to expand into a vacuum is because all of the particles of the gas are hitting each other and then bouncing further away from each other, and absolutely not because the vacuum is yoinking them in any way? It’s the same reason a gas wants to uniformly fill an enclosed space.

Even when talking about a leak rather than a rocket exhaust, the vacuum isn’t acting on the gas, the gas is escaping into the vacuum, by its particles bouncing off into it via millions of tiny bouncy collisions with other bits of gas and any container walls that are involved.

It’s not like the gas particles queue up in an orderly way to leave into the vacuum making sure they are not jostling any other particles or solid surfaces on their way out, because they want to make sure they are not transferring any energy

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Old 19th April 2019, 01:31 PM   #464
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Originally Posted by MRC_Hans View Post
Originally Posted by Gingervytes View Post
Hot air rises because temperature makes the pressure go up and this creates a pressure gradient.

http://ww2010.atmos.uiuc.edu/(Gh)/gu.../prs/hght.rxml
Nonsense. Hot air rises because it is lighter than cool air. What has this to do with rockets?

I'm serious here: If you keep doing this, I'll report you for derailing.

Hans

Gingervytes probably doesn't mean that the pressure increases. He/She probably means that it goes up!!! Literally!
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Old 19th April 2019, 02:26 PM   #465
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Originally Posted by Gingervytes View Post
And in the case of a rocket. Pressure expands due to pressure gradient force and not because the rocket pushes it
Trying to make some sense of your statement, but no luck, sorry...
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Old 19th April 2019, 02:36 PM   #466
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Originally Posted by dann View Post
Gingervytes probably doesn't mean that the pressure increases. He/She probably means that it goes up!!! Literally!
Equally nonsensical.

Hans
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Old 19th April 2019, 02:44 PM   #467
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Curious Cat:
"If he "pushed" the weight down while it was falling to accelerate its descent over 9.81m/s^2, he could achieve a point where he would lift himself from the ground. I don't think anybody is fit enough to achieve this though ;-)."

Originally Posted by JayUtah View Post
.................................................. ......

No, but if you were standing on a scale and threw something vigorously at the floor, you would be able to measure a reduction in your weight. There would be upward thrust, but not enough to levitate you.
.................................................. ..
I beg to differ. Why do you think it is not possible to to cause upward motion (you call it "levitation" if you wish ;-)) - while exerting a downward force on a falling object? I indicated I don't believe it is possible with human physical limitations, but in absolute terms it is perfectly possible. It is a simple maths, after all, but a little example may serve better: a falling bomb explodes in mid air. Do you seriously think you would be safe from its shrapnel if you are above it? I do not propose to try :-).

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Old 19th April 2019, 02:54 PM   #468
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Originally Posted by Lithrael View Post
Is it too late to point out that the reason why a gas wants to expand into a vacuum is because all of the particles of the gas are hitting each other and then bouncing further away from each other, and absolutely not because the vacuum is yoinking them in any way? Itís the same reason a gas wants to uniformly fill an enclosed space.

Even when talking about a leak rather than a rocket exhaust, the vacuum isnít acting on the gas, the gas is escaping into the vacuum, by its particles bouncing off into it via millions of tiny bouncy collisions with other bits of gas and any container walls that are involved.

Itís not like the gas particles queue up in an orderly way to leave into the vacuum making sure they are not jostling any other particles or solid surfaces on their way out, because they want to make sure they are not transferring any energy
Reading a description of that whole "silly string" explanation, and about vacuums pulling things, I wondered if that is the source of the OP's confusion, and of whoever else might hold the same theories.

If you talk about our most familiar form of vacuum, which is a vacuum cleaner, a lot of people probably have an idea that the vacuum cleaner is exerting a force that lifts the dust or paper or whatever. I never thought about it before, but that's not really true is it? What's really happening is that the existence of the vacuum creates wind, and the wind blows things into the nozzle of the vacuum cleaner.

If you thought that somehow the existence of a vacuum exerted a force on a gas, you could get some pretty messed up ideas about how things worked.
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Old 19th April 2019, 02:55 PM   #469
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Originally Posted by MRC_Hans View Post
And how is this relevant for the topic? A gun is optimized to exploit the cartridge charge to propel a bullet, so this is what it does best. If we optimized it differently, as a rocket, that same charge would work best for that.

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O.K., sorry if I ruffled your feathers. The first part was perfectly relevant to the topic, debunking the principle of rocket (gun) pushing itself from some outside object (bullet). In the rest of my incoherent blabbering I am trying to preempt possible objections by the OP.
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Old 19th April 2019, 02:56 PM   #470
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Originally Posted by curious cat View Post
I beg to differ. Why do you think it is not possible to to cause upward motion (you call it "levitation" if you wish ;-)) - while exerting a downward force on a falling object? I indicated I don't believe it is possible with human physical limitations, but in absolute terms it is perfectly possible.
No need to differ; we're in substantial agreement. I'm stating the equivalent case that would arise under normal human strength. If it were practicable for you to throw a solid mass downward with enough velocity, actual upward motion could be achieved. There is no theoretical problem with levitation according to that method. You'd just be a mechanical rocket. My case states that throwing a mass downward with ordinary human strength could result in a reactive force that lessens your weight momentarily, even if you didn't achieve liftoff. You'd be a mechanical rocket with an underpowered engine. Thrust is still generated, and that thrust could be measured by noting how it subtracts from gravity, by the scale. You just wouldn't fly.

Sorry for the confusion.
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Old 19th April 2019, 03:17 PM   #471
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Originally Posted by MRC_Hans View Post
Because of gravity. Gravity holds it back.

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You have to remember most of the 'no such thing as space' crowd think gravity is a hoax.
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Old 19th April 2019, 03:20 PM   #472
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Originally Posted by JayUtah View Post
No need to differ; we're in substantial agreement. I'm stating the equivalent case that would arise under normal human strength. If it were practicable for you to throw a solid mass downward with enough velocity, actual upward motion could be achieved. There is no theoretical problem with levitation according to that method. You'd just be a mechanical rocket. My case states that throwing a mass downward with ordinary human strength could result in a reactive force that lessens your weight momentarily, even if you didn't achieve liftoff. You'd be a mechanical rocket with an underpowered engine. Thrust is still generated, and that thrust could be measured by noting how it subtracts from gravity, by the scale. You just wouldn't fly.

Sorry for the confusion.
You can demonstrate something similar by moving yourself across the floor on an office chair. Just throw something across the office.
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Old 19th April 2019, 03:26 PM   #473
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Originally Posted by JayUtah View Post
Technically and ironically correct, a double-whammy. If the Earth and the weight move closer together, and the person who let loose the weight is standing on a scale, then the Earth and the person are inertially coupled and the lateral acceleration imposed by the Earth moving to meet the weight will result in a greater weight measured on the scale. It will be the sum of the gravitational attraction between the Earth and the person, and the reaction to the acceleration of the Earth toward the weight, as produced in the person.

A related problem occurs in actual rocketry when you model the spacecraft as a Newtonly-connected pile of components that comprises a system of inertially- and mechanically-coupled elements. The various submasses of a rocket are not rigid, but act like individual masses connected semirigidly. Then there is also fuel slosh, the effects of the mass of propellant wallowing around in the tanks. Elon Musk had some difficulty with this in the early Falcons. It's part of the overall problem of dynamic spacecraft control.
Several years later, I'm still coming down from the high of discovering ullage motors.
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Old 19th April 2019, 03:31 PM   #474
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Originally Posted by bknight View Post
FTFY, I know you really didn't mean to type that Newtonian physics is a theory.
I actually can't see anything wrong with it. In the world of science the word "theory" has a broader meaning and doesn't necessarily mean something uncertain or unproven.
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Old 19th April 2019, 03:40 PM   #475
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Originally Posted by curious cat View Post
I actually can't see anything wrong with it. In the world of science the word "theory" has a broader meaning and doesn't necessarily mean something uncertain or unproven.
Yup, science is theory explaining observation.

"A*scientific theory*is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported*theories*are not "guesses" but reliable accounts of the real world."
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Old 19th April 2019, 03:47 PM   #476
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Originally Posted by JayUtah View Post
No need to differ; we're in substantial agreement. I'm stating the equivalent case that would arise under normal human strength. If it were practicable for you to throw a solid mass downward with enough velocity, actual upward motion could be achieved. There is no theoretical problem with levitation according to that method. You'd just be a mechanical rocket. My case states that throwing a mass downward with ordinary human strength could result in a reactive force that lessens your weight momentarily, even if you didn't achieve liftoff. You'd be a mechanical rocket with an underpowered engine. Thrust is still generated, and that thrust could be measured by noting how it subtracts from gravity, by the scale. You just wouldn't fly.

Sorry for the confusion.
No problems. I was sure it wasn't a lack of knowledge on you part, but an obvious overlook of this part of my post:
"I don't think anybody is fit enough to achieve this though ;-)".
BTW, it wasn't based only on my personal assessment, but also on an excellent Mythbusters' episode. They were trying to find out, if you can save yourself by jumping up from a collapsing bridge when it starts falling. The answer was a clear "NO".

Last edited by curious cat; 19th April 2019 at 03:51 PM.
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Old 19th April 2019, 04:22 PM   #477
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Originally Posted by Dabop View Post
I was just thinking (a dangerous thing to do at the best of times for me)- that 'technically' wouldn't dropping a weight actually lift you???

You are standing holding a weight, and release it
Now (and this is just my musings) when you release the weight, it and the earth are mutually attracted, the weight will move (a lot) towards the earth, and the earth will move (microscopically) towards the weight
You (standing on the earths surface) would also be 'lifted' by this movement of the earth

So technically you would move (ever so incredibly tiny an amount) in the opposite direction to the direction of the weight's travel

I think this is correct?
The only thing wrong with it is, we are moving in areas of physic which we should avoid in discussions with Gingervytes. I believe the KISS principle should be the name of the game :-).

Last edited by curious cat; 19th April 2019 at 05:16 PM.
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Old 19th April 2019, 04:40 PM   #478
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Originally Posted by curious cat View Post
No problems. I was sure it wasn't a lack of knowledge on you part, but an obvious overlook of this part of my post:
"I don't think anybody is fit enough to achieve this though ;-)".
Neither. I read and agreed with your proviso. What I feared -- given the tendency in these threads to misunderstand accidentally or on purpose -- was that someone would think that no thrust would be produced in the practical case. Given the almost certain fact that no human can reach orbit by vigorously hurling cabbages, I felt it was still important to understand what the physics would be -- specifically that thrust will still be produced, just on a smaller scale. Then I thought about how one would measure that effect, and I hit upon the ... smaller scale.
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Old 19th April 2019, 05:09 PM   #479
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Originally Posted by Lithrael View Post
Is it too late to point out that the reason why a gas wants to expand into a vacuum is because all of the particles of the gas are hitting each other and then bouncing further away from each other,
Gas molecules Simulation
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Old 19th April 2019, 11:59 PM   #480
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Originally Posted by Captain_Swoop View Post
You have to remember most of the 'no such thing as space' crowd think gravity is a hoax.
I know, but I want them to say so right out. Thing is that gravity (in the form of mass attraction) is empirically confirmed.

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