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Re: [Phys-l] in need of textbooks

OK. Our book sale is over, and I've collected four copies of the sixth edition. Will this number help?

-----Original Message-----
[]On Behalf Of frank
Sent: Monday, May 14, 2007 1:03 PM
To: Forum for Physics Educators
Subject: Re: [Phys-l] in need of textbooks

I can use up to 40 textbooks so whatever you can spare would be appreciated. I will pay for the mailing costs. Let me know if this works for you. My school mailing address is below:
Frank Cange
Trinity HS
1720 redman ave
St.Louis,Mo 63138
Thanks again!> Date: Mon, 14 May 2007 10:53:30 -0500> From:> To:> Subject: Re: [Phys-l] in need of textbooks> > I'm changing books next year, so I can probably scare up a 6th edition.> skip> > -----Original Message-----> From:> []On Behalf Of frank> cange> Sent: Monday, May 14, 2007 10:42 AM> To: Forum for Physics Educators> Subject: [Phys-l] in need of textbooks> > > > Dear COlleagues:> I am in need of new physics textbooks and there is no budget money to buy them. If anyone has PHYSICS: PRINCIPLES WITH APPLICATIONS BY GIANCOLI, a newer ed. than 1998 that they are willing to donate please contact me. Thanks in advance!Frank Cange> Physics Teacher> Trinity Hs> 1720 redman ave> St.Louis,MO 63138> Date: Fri, 11 May 2007 21:39:43 -0500> From:> To:> Subject: Re: [Phys-l] The nature of force fields.> > I have no quarrel with John's reply, I would have stated it more > succincly.> A force field is a vector field (a mathematical concept). A > vector field assigns a vector to each point of space (at a particular > time). The vector is the force, associated with the point.> I have high school students illustrate this concept in class by > rising, on commant, with each student holding out his/her arm, pointing in > some individually chosen direction. The students are illustrating a > vector field, each arm denoting a vector associated with the point where > the student is located.> > > > > On Thu, 10 May 2007, John Denker wrote:> > > On 05/10/2007 03:13 AM, Tibor G Molnar wrote:> >> >> It occurs to me that the definition of 'force fields', such as> >> gravitational fields, is circular.> >> > I prefer to think of it as incomplete rather than circular.> > See below for details.> >> >> When we ask "what is a force field?",> >> we are told that it is a region of spacetime where some or other material> >> object experiences a force. And when we ask "how/why does an object> >> experience a force in some region of spacetime?", we are told that it is> >> due to the presence of a force field.> >>> >> But what is a force field "really"? In order to exert a force (whether> >> pushing or pulling) on material objects, a force field needs logically to> >> be the effect of some or other real, physical "goings on". But what? Do> >> we have a mechanical, causal explanatory account of what a force field> >> "actually" is?> >>> >> More particularly, how can I understand (without ultimately appealing to> >> some or other Einsteinian "spooky action at a distance") how, in the case> >> of gravity for example, one physical object can remotely 'pull' another?> >> To pull something, don't we need a line with a hook on the end?> >>> >> I am familiar with Einstein's explanation in terms of warped spacetime; but> >> as far as I can tell, that is just an instrumentalist account, with little> >> causal explanatory power. Is there a better explanation?> >> > In a small way yes, there are more-detailed explanations> > for each of the known forces. But if I gave you the> > more-detailed explanation, you would just re-ask the same> > sort of questions at a more-detailed level.> >> > So the big answer is that such questions are by-and-large> > unscientific. This is one of the big breakthroughs that> > Galileo made: He realized that it sufficed to say what> > would happen under such-and-such conditions; he did not> > need to say /why/ it happened.> >> > Specifically:> >>> The present does not seem to me to be an opportune time to enter> >>> into the investigation of the cause of the acceleration of> >>> natural motion, concerning which various philosophers have> >>> produced various opinions ....> >>> Such fantasies, and others like them, would have to be> >>> examined and resolved, with little gain. For the present, it> >>> suffices .... to say that in equal times, equal> >>> additions of speed are made.> >>>> >>> Galileo, _Two New Sciences_ (1638).> >> > This was a major departure from how things had been done previously.> >> > Newton echoed this point more concisely in his famous pronouncement> > "hypotheses non fingo".> >> > The question of "what happens" is physics.> > The question of "why" is (usually) metaphysics.> > If people want to discuss metaphysics, that's OK; I just ask that> > they not get in my way when I'm trying to do physics.> >> >> > It is important to distinguish between nature and models. First,> > last, and foremost, nature is what it is, and does what it does.> > Meanwhile, models are made by people for people, to help us predict> > what nature is going to do. All the models are imperfect.> > -- You are free to ask for a more-detailed or less-detailed model.> > Electrostatics? Classical electrodynamics? Quantum electrodynamics?> > Take your pick.> > -- You are free to ask whether a counterintuitive model could be> > made more intuitive ... but this is a moving target, because as> > the proverb says, education is the process of cultivating your> > intuition.> > -- You are free to ask whether this-or-that model is consistent> > with some other model, and/or consistent with observations.> > -- All models are imperfect. It's not helpful to complain about> > this-or-that model unless you've got something better to offer.> >> > Asking for a "mechanical" model of what's going on is almost certainly> > a step in the wrong direction. Lots of people have tried over the> > years, and the uniform experience is that the mechanical models work> > less well than the more abstract field models.> >> > Mostly we write field equations because we can. They are mathematically> > tractable and do an excellent job of predicting what will happen under> > a large (albeit not infinite) set of conditions.> >> > _______________________________________________> > Forum for Physics Educators> >> >> >> > -- > "Trust me. I have a lot of experience at this."> General Custer's unremembered message to his men,> just before leading them into the Little Big Horn Valley> > > > _______________________________________________> Forum for Physics Educators>>> _________________________________________________________________> Change is good. See what’s different about Windows Live Hotmail. >> _______________________________________________> Forum for Physics Educators>>> > _______________________________________________> Forum for Physics Educators>>
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