What keeps electrons spinning around their nucleus?
in [Relativity]
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From: mmeron on 28 Mar 2005 18:32 In article <slrnd4h9dg.6h5.dubious(a)radioactivex.lebesque-al.net>, dubious(a)radioactivex.lebesque-al.net (Bilge) writes: > mmeron(a)cars3.uchicago.edu: > > >I don't see anything in the formulation of newton's laws saying that > >forces must be traceable to fundamental interactions. What should be > >taught is that there are "physical forces" which are, indeed, a > >measure of interactions between objects, and there may be additional > >"inertial forces" which are an artifact of the choice of reference > >frame. But being an artifact, does not mean that they've no > > ``Inertial force'' is an oxymoron. If ``inertial forces'' are >to be considered forces, then the word ``force'' is nothing but >a placeholder for a noun, since anything is then a force. > Not "anything". Just anything that can be plugged into f = ma to yield equations of motion. You can use, say, the Coriolis force in this way, but I doubt very much that pepperoni pizza will work. Mati Meron | "When you argue with a fool, meron(a)cars.uchicago.edu | chances are he is doing just the same"
From: mmeron on 28 Mar 2005 18:56 In article <d2a04r0riu(a)drn.newsguy.com>, stevendaryl3016(a)yahoo.com (Daryl McCullough) writes: >mmeron(a)cars3.uchicago.edu says... > >>There is ***nothing*** wrong with centrifugal force. The term >>"fictitious" is misleading. True, it doesn't stem from interaction, >>just from choice of reference frame. So? It is quite often convenient >>to deal with a problem in an accelerated frame, rather than transform >>to an inertial frame and back. And when you want to deal with a >>problem in the accelerated frame and still use Newton's laws, you >>include inertial forces (i much prefer the term "inertial" than the >>misleading "fictitious"). > >I don't think that there is anything wrong with using noninertial >coordinates, but I think what is misleading is to call the correction >terms "forces". Only if you attach more meaning to the term "force" than it deserves. > >I know that's just terminology, but the way I see it, inertial >forces result from using noninertial coordinates, but *pretending* >that they are inertial. Yeah. So? > What I mean is this: Noninertial coordinates >mean that your basis vectors e_i are not constant. So if you define >the acceleration vector A to be the time derivative of the velocity >vector V, you get > > A = d/dt V > = d/dt (V^i e_i) > = e_i (d/dt V^i) + V^i (d/dt e_i) > >The use of "fictitious forces" amounts to pretending that >the second term is a *force* term, rather than what it really >is, an *acceleration* term. If we start with > > F = m A > >and move the second term to the other side of the equation, we get > > F - m V^i (d/dt e_i) = e_i (d/dt V^i) > >and then the extra acceleration term looks like an extra force term, >if we define > > F_inertial = - m V^i (d/dt e_i) > >So, while I agree with you that using noninertial coordinates can be >convenient, there really is no *convenience* benefit to treating the >extra term as a fictitious force, instead of what it is, an acceleration >term. > Now, why should I make a distinction. I'm solving an equation of motion, meaning my goal is to obtain r(t), not some "inner truth". And, in the equation of motion I've various terms, some resulting from interactions, other from my choice of reference frame, but all entering at the same standing and treated the same. So, I would say just the opposite to what you said above, namely that there is *absolutely* no benefit in treating the extra term as something different, instead of just as forces. Mati Meron | "When you argue with a fool, meron(a)cars.uchicago.edu | chances are he is doing just the same"
From: TomGee on 28 Mar 2005 19:01 PD wrote: > TomGee wrote: > > Wormy, Bilge, PD, and all you other lemmings, > > > > you cannot understand that it is the _measurement_ of the force which > > is fictional and not the feeling of being pulled out as a carousel > > spins. > > Nope. You feel the force pulling you *in*, which is a force you are > unaccustomed to, and so you mistakenly associate that with a force > pulling you out. Your naive interpretations are what's tripping you up. > > Next time you're on a carousel, PD, let go and fall in toward the center ofit, ok? I am glad you agree that it is the measurements which are fictional and not the force (though Otherwise you would have made some attempt at disagreeing with that, right?). > > > Let me ask you another question. As an elevator suddenly starts to > descend, you feel lighter. Are you in fact lighter? Why should Earth's > gravity pull on you less just because the floor of the elevator started > to go down? > > Let me ask you another question. You are on a road making a circular > bend left in your car. What force acting on the car enables you to > change your straight-line motion? You hit an icy patch in the middle of > the turn. What happens to your car? Does it go *straight* or does it go > *outward*? What force has disappeared when you hit the icy patch? > > > You cannot make the force disappear just by invalidating your > > own measurements. You should not think that websites are the > ultimate > > authority on anything, either, as subjective opinion runs rampart all > > through it. > > Which is why I reference textbooks, Tom. Which you refuse to read. > > No, I don't. I already read them, and they did not support your claims. > > > > You will learn that, Bilgy, when if ever you get to the > > fifth grade. > > > > You call us lemmings, Tom, but we're pointing out things that really > are basic, classical physics. > > No, you're not. Your claims are even wilder than mine, and you refuse to support them. Your interpretations of common terms are so far off that they don't even make sense. That is because you only read opinionated wefsites claiming to be factual when they are misinterpretations of the facts. And you with the others fell right in step without looking for the flaws in the fallacious claim that because the measurements are false, the force is false as well. > > > If you want to uproot that, then > advertise that what you're doing is uprooting not only special > relativity, but also Newtonian physics, classical kinematics, and just > about everything else too. But if you don't want to claim that, then > learn a little physics so you know where the dividing line is. > > But it is you, PD, who needs to learn a little physics more than I do since you seem to always get it wrong. TomGee
From: TomGee on 28 Mar 2005 19:07 Of course I am, Sam, as it is not my idea and it is not from classical physics but from quantum mechanics (now more commonly called quantum physics, it seems). TomGee
From: TomGee on 28 Mar 2005 19:11
No, one mustn't, PD, one must get de-brainwashed first before one can come up with an original idea. But if you're going to argue accepted science, you should learn it first. TomGee |