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Post by striker16 on Sept 12, 2012 10:45:44 GMT 1
It opposes gravity because it seeks to maintain its momentum (mass x velocity).
I am not an expert on gyros so cannot provide further information, however, the key thing to remember is that a spinning wheel, which has had a force applied to it, is no longer just under the influence of gravity. A thrown rock rises in the air due to the force applied to it by the thrower and opposes gravity until its linear momentum runs out.
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Post by mrsonde on Sept 12, 2012 15:37:08 GMT 1
I repeat, angular momentum is not a force. Gravity is the only force involved here - the rest is inertia. It requires a force to change the motion of that inertial mass - that's Newton, or Einstein. In this case it's the force of Laithwaite's muscles - the question is by what are those muscles apparently being assisted in this case? If you're saying it's an angular momentum acting upwards, against the pull of gravity, then this would be measurable, and predictable, acccording to the equations. It would result in the reduction in weight if the shaft was fixed to a bench, over a set of scales. Intuitively, we all know there would be no such reduction in weight, don't we?
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Post by mrsonde on Sept 12, 2012 15:48:31 GMT 1
It opposes gravity because it seeks to maintain its momentum (mass x velocity). It's air resistance and the friction on the bearings that's opposing its continued momentum, not gravity, anymore than the Earth's rotation is opposed by the Sun or Moon's gravitational attraction. (There's a minor effect because of mountains or oceans, or slight imbalances perhaps in Laithwaite's wheel; but ideally there is no opposition to the momentum from gravity.) What there is opposition to is Laithwaite's altering the axis of rotation vis a vis the external force, gravitation. This produces a torque and turns him around, at right angles to both, acording to the Fleming rule: not upwards.
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Post by mrsonde on Sept 12, 2012 15:55:19 GMT 1
nless I've missed a key stage in your argument, all you seem to be saying Striker is that this phenomenon is caused by angular momentum. That is, it's stating the obvious, and no one has ever disagreed. The issue is: how is "angular momentum" causing this effect? How do the classical (or relativistic) equations of angular momentum apply to this situation, so that it's an expected rather than a surprising occurrence? Without such an explication, you may as well replace "angular momentum" in your explanation by "magic".
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Post by striker16 on Sept 12, 2012 15:55:24 GMT 1
I repeat, angular momentum is not a force. Gravity is the only force involved here - the rest is inertia. It requires a force to change the motion of that inertial mass - that's Newton, or Einstein. In this case it's the force of Laithwaite's muscles - the question is by what are those muscles apparently being assisted in this case? If you're saying it's an angular momentum acting upwards, against the pull of gravity, then this would be measurable, and predictable, acccording to the equations. It would result in the reduction in weight if the shaft was fixed to a bench, over a set of scales. Intuitively, we all know there would be no such reduction in weight, don't we? Oh dear. Inertia is the reluctance of either a stationary or moving body to change its state. Answer me this: where did the spinning wheel obtain its 'spin' from? Yes, a drill, powerered by electromotive force, so what are you on about? You can't destroy energy, only change its form, remember? Presumably, you do not agree with Newton! How radical. I've already said the wheel does not lose weight, in the same way a space rocket does not lose weight, however they are both under the influence of a counter-force which opposes the force of gravity. There would seem to be a reduction in weight, as shown by Braithwaite's demonstration, because he was able to hold the wheel and shaft easily, but this is only because the wheel is under the influence of angular momentum and wants to remain in its position; in this respect the inertia of the wheel applies. Are you suggesting a person bouncing on a trampoline loses weight because he/she is projected upwards by the reactive force of the trampoline?
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Post by mrsonde on Sept 12, 2012 16:06:47 GMT 1
I repeat, angular momentum is not a force. Gravity is the only force involved here - the rest is inertia. It requires a force to change the motion of that inertial mass - that's Newton, or Einstein. In this case it's the force of Laithwaite's muscles - the question is by what are those muscles apparently being assisted in this case? If you're saying it's an angular momentum acting upwards, against the pull of gravity, then this would be measurable, and predictable, acccording to the equations. It would result in the reduction in weight if the shaft was fixed to a bench, over a set of scales. Intuitively, we all know there would be no such reduction in weight, don't we? Oh dear. It's mister Sonde. Just in case you were confused about it. I'm merely pointing out that angular momentum is not a force, able to oppose anything, or act externally, as your sentence structures strongly implied. That's all. As you say, its only difference to linear momentum is it's curvilinear. You wouldn't say motion is a force, would you? That's not Newton, but never mind. We're not talking about destroying energy. The principle of the conservation of angular momentum is being observed by the presence of the torque. If Laithwaite didn't turn in a circle, he'd have his arm torn out of his socket when he altered the shaft's axis. In the application on his rowing boat, this energy propelled him through the water. (Not up int he air!) It is indeed radical. that's why this demonstration caused such a furore. But all that is required is not a fuss, but a simple answer. A simple calculation according to 300 year-old equations of accepted physics, showing how this angular momentum is acting against gravity to cause an x reduction in weight.
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Post by striker16 on Sept 12, 2012 16:12:51 GMT 1
You are talking rubbish, sorry. Why is Braithwaite considered a crank?
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Post by mrsonde on Sept 12, 2012 16:16:41 GMT 1
You are talking rubbish, sorry. In what way am I talking rubbish? If you don't know, you should indeed apologise, because you're merely being unjustifiably insulting. This is supposed to be a science board, is it not? Who?
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Post by mrsonde on Sept 12, 2012 16:34:12 GMT 1
I presume you mean Laithwaite. He's not, in general, considered a crank. In general, he's considered one of the most innovative and brilliant engineers this country has ever produced. He was labelled a crank by certain elements of the Physics community following this demonstration. When all that was required was a simple answer addressing the issue - an issue that they claim is elementary Newtonian physics. Clearly it's not, because no one has ever been able to give such an answer. On the other hand, half a dozen other questions to do with gyroscopic motion were more or less satisfactorily answered (the more or less is significant - Laithwaite wasn't wrong, or cranky; merely that a full description of a gyroscope's behaviour requires more than Newton's Laws of Motion), so why was this one so assiduously ignored? Because it's unanswerable, I'd suggest.
In any case, the list of scientists who were once labelled cranks and invarious familiar ways ostracised by the scientific establishment for their anti-consensual arguments is very long. It's actually the norm. I can think of a dozen such examples off the top of my head, just from the past thirty years - lasers, masers, prions, box genes, cell symbiosis, interstellar plasma, MHD interactions in the magnetosphere, the Maunder and other minima in the sunspot record, etcetera etcetera. The scientific community labelling a lone dissenter to the accepted paradigmatic theories means nothing - it's an expected defensive reaction by people who's career paths and sense of standing is felt to be threatened by someone saying that they're mistaken, that's all. The logical and decent response should be a clear and decisive explanation of how the mistake is rather on the dissenter's side - when this doesn't happen, it's a very good indication that the dissenter has instead put their finger on a crucial mystery, a fault in the paradigm.
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Post by mrsonde on Sept 12, 2012 16:39:23 GMT 1
The greatest example of this is Herbert Dingle, in my opinion. A still unsettled dispute, well over half a century later. Eventually, I have no doubt whatsoever, Dingle's objections to the standard interpretation of Special Relativity will be found to be correct, and all those physicists who dismissed and insulted him, and gave half a dozen completely irrelevant or plain incorrect answers to his objections, will be assessed - in the light of a unified theory of quantum gravity - to have missed his point entirely. Exactly the same applies in this case, I believe.
As for the global warming fiasco...
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Post by striker16 on Sept 12, 2012 16:43:51 GMT 1
"...Laithwaite suggested that Newton's laws of motion could not account for the behaviour of gyroscopes and that they could be used as a means of reactionless propulsion. The members of the Royal Institution rejected his ideas and his lecture was not published. (This was the first and only time an invited lecture to the Royal Institution has not been published.)" en.wikipedia.org/wiki/Eric_Laithwaite#Biography
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Post by mrsonde on Sept 12, 2012 17:04:23 GMT 1
And he was quite right. The full explanations of the issues he raised in that lecture, which he graciously accepted, strayed well beyond Newton's Laws of Motion. As for the reactionless propulsion, he was correct about that too, as the second demo I posted shows.
The lecture was published. Just not by the Royal Institution. You have to ask yourself why, when nothing he said in that fascinating lecture was shown to be incorrect.
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Post by mrsonde on Sept 12, 2012 17:11:17 GMT 1
But it's interesting to bear in mind Laithwaite's background, and where he's coming from with these questions. His principal field is electrical engineering - his mind is working primarily with Maxwell's electromagnetic equations, not Newton's Laws of Motion. The irreconcilable clash between them was of course settled by Einstein in Maxwell's, not Newton's, favour. Now one of the lesser known implications of Maxwell's equations is a displacement current arising from a rotationary field - there's no analogy in Newton, or the equations of angular momentum: Laithwaite is suggesting that this "anti-gravity" force is the appropriate analogy. That is, were this an electromagnetic set-up, Maxwell's equations predict just such a loss in "weight"; Newton's do not.
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Post by striker16 on Sept 12, 2012 17:28:59 GMT 1
But it's interesting to bear in mind Laithwaite's background, and where he's coming from with these questions. His principal field is electrical engineering - his mind is working primarily with Maxwell's electromagnetic equations, not Newton's Laws of Motion. The irreconcilable clash between them was of course settled by Einstein in Maxwell's, not Newton's, favour. Now one of the lesser known implications of Maxwell's equations is a displacement current arising from a rotationary field - there's no analogy in Newton, or the equations of angular momentum: Laithwaite is suggesting that this "anti-gravity" force is the appropriate analogy. That is, were this an electromagnetic set-up, Maxwell's equations predict just such a loss in "weight"; Newton's do not. Where is your evidence?
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Post by mrsonde on Sept 12, 2012 17:40:38 GMT 1
Evidence for what, sorry?
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