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| Tags: classical, modified, physics, postulates |
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#11
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#12
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In article ,
John Schoenfeld wrote: (Gregory L. Hansen) wrote in message ... In article , John Schoenfeld wrote: POSTULATES OF A MODIFIED CLASSICAL PHYSICS Inertia law: Mass is a scalar velocity field: Scalar form: m(v) = m0 + int(0,v) (dm/dv) . dv Vector form: m(v) = m0 + intP(0,v) grad_v(m) . dv 1st Law of Motion: The momentum of a body remains invariant unless otherwise acted on by a Force. Scalar form: p = m(v) v Vector form: p = m(v) v 2nd Law of Motion: Force is the 1st time derivative of momentum. Scalar form: F = (m + v dm/dv) a Vector form: F = (m + v . grad_v(m))a 3rd Law of motion: Interacting bodies conserve net momentum through equal and opposing Forces. How are these modified postulates? They look like Newton's postulates to me, except you've specialized them to a mass that varies with velocity in an unspecified way (what's dm/dv?). It's still p=mv, F=dp/dt, and conservation of momentum. No, it's p = m(v)v. The different is important. Yes, because Newton's p=mv doesn't specify that m is *not* a function of velocity. In fact, a velocity-dependent mass had been used in the 19th century in electrodynamics calculations, and later became known as relativistic mass when it was realized that a quasi-Newtonian analysis of some relativistic systems can be done by substituting m-m/sqrt(1-v^2/c^2). You don't have new postulates. You've specified that m=m(v), without giving the form of m(v) or the nature or physical meaning of its velocity dependence, and then derived a force law from the old postulates. -- "The polhode rolls without slipping on the herpolhode lying in the invariable plane." -- Goldstein, Classical Mechanics 2nd. ed., p207. |
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#13
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Uncle Al wrote in message ...
John Schoenfeld wrote: POSTULATES OF A MODIFIED CLASSICAL PHYSICS 1) YOU ARE AN IDIOT. 2) LEARN HOW TO USE YOUR SHFIT KEY. I am an idiot because I used caps? Think before typing, idiot (by your own definition). 3) You are an idiot. Think. |
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#15
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"Franz Heymann" wrote in message ...
"John Schoenfeld" wrote in message om... "Franz Heymann" wrote in message ... "John Schoenfeld" wrote in message m... POSTULATES OF A MODIFIED CLASSICAL PHYSICS Inertia law: Mass is a scalar velocity field: Scalar form: m(v) = m0 + int(0,v) (dm/dv) . dv That is brand new. Why did you change your old approach? Wrong. It's a direct consequence from the fundamental theoreom of calculus. m(v) - m(u) = int(0,v) (dm/dv).dv in vector form: m(v) - m(u) intP(u,v) grad_v(m).dv Vector form: m(v) = m0 + intP(0,v) grad_v(m) . dv So which one are we supposed to choose, vector or scalar? Newton's Laws can be expressed in Scalar form or Vector form, what's your problem with what i have posted above? My problem is that Newton's Laws refer only to the vector quantities acceleration, force, momentum, etc. 1st Law of Motion: The momentum of a body remains invariant I think you mean constant. Invariant has to do with the behaviour of a quantity when changing frames of reference. In my opinion, they are invariant and constant are equal. No.. Before you came on the scene, the word "invariant had acquired a quite specific usage. *Not* to be confused with "constant". You are, of course, welcome to use exisging terms with meanings privatew to you, but I would not advise it if you are trying to convince folk that you are not just cheering from the side lines. unless otherwise acted on by a Force. Scalar form: p = m(v) v That is not an expression for a force That's right, it's the expression for momentum.You said it was an expression for force. Reread what you said. Vector form: p = m(v) v That, also, is not an expression for a force That's right, it's the expression for momentum. That's not what you said. And a force is *always* a vector. For a lot of problems, Force can be treated as a scalar - |F|. |F| is the magnitude of the froce vector F. Force is *always* a vector. 2nd Law of Motion: Force is the 1st time derivative of momentum. Scalar form: F = (m + v dm/dv) a There is no such thing as a scalar force. Wrong. It's just the length of the Force vector, and v the length of the velocity vector, which are scalars. In that case you are still wrong, because the acceleration is a vector. You should learn to express yourself clearly, correctly and unambiguously. Vector form: F = (m + v . grad_v(m))a These equations disagree with the definitions you gave higher up for force, where you called it "p" for some unknown reason. That was a disastrous typo that I made. The "Vector" form is: F = m(v) a + v(grad_v(m) . a) Proof: p = m(v) v dp/dt = m(v) dv/dt + v(grad_v(m) . dv/dt) Why not just keep it simple, and just say dp/dt = m dv/dt + v dm/dt ? Sure, since dm/dt = grad_v(m) . a. PROOF: dm/dt = d/dt m(v(t)) = grad_v(m) dv/dt 3rd Law of motion: Interacting bodies conserve net momentum through equal and opposing Forces. That is not a law of motion. It is deducible from the 3rd law of motion. (I hasten to say that I refer to Newton's 3rd law, not your crap.) It is Newtons 3rd law. No. At the stage at which newton's laws are initially presented, momentum has not yet been defined. Newton's 3rd law says "An action is always opposed by an equal and opposite reaction" There is no mention of momentum conservation there. The latter is derived a page or two later, after "momentum" has been defined". I do most sincerely hope that you are not just aiming to give us a repeat performance of the crap you posted earlier. Franz |
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#17
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#18
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#19
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In article ,
John Schoenfeld wrote: (Gregory L. Hansen) wrote in message ... In article , John Schoenfeld wrote: (Gregory L. Hansen) wrote in message ... In article , John Schoenfeld wrote: POSTULATES OF A MODIFIED CLASSICAL PHYSICS Inertia law: Mass is a scalar velocity field: Scalar form: m(v) = m0 + int(0,v) (dm/dv) . dv Vector form: m(v) = m0 + intP(0,v) grad_v(m) . dv 1st Law of Motion: The momentum of a body remains invariant unless otherwise acted on by a Force. Scalar form: p = m(v) v Vector form: p = m(v) v 2nd Law of Motion: Force is the 1st time derivative of momentum. Scalar form: F = (m + v dm/dv) a Vector form: F = (m + v . grad_v(m))a 3rd Law of motion: Interacting bodies conserve net momentum through equal and opposing Forces. How are these modified postulates? They look like Newton's postulates to me, except you've specialized them to a mass that varies with velocity in an unspecified way (what's dm/dv?). It's still p=mv, F=dp/dt, and conservation of momentum. No, it's p = m(v)v. The different is important. Yes, because Newton's p=mv doesn't specify that m is *not* a function of velocity. In fact, a velocity-dependent mass had been used in the 19th century in electrodynamics calculations, and later became known as relativistic mass when it was realized that a quasi-Newtonian analysis of some relativistic systems can be done by substituting m-m/sqrt(1-v^2/c^2). You don't have new postulates. You've specified that m=m(v), without giving the form of m(v) or the nature or physical meaning of its velocity dependence, and then derived a force law from the old postulates. Mass as a scalar function: m(v) = m0 + int(0,v)(dm/dv)dv Mass as a vector function: m(v) = m0 + intP(0,v) grad_v(m). dv Okay, so you know the fundamental theorem of calculus, and you've postulated that dm/dv is at least peice-wise differentiable. I suppose that's progress, of a sort. At least we know the function is defined for all v, and doesn't have pathological behavior like a Koch curve. But that doesn't narrow it down very much unless we know dm/dv. -- "For every problem there is a solution which is simple, clean and wrong." -- Henry Louis Mencken |
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#20
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"John Schoenfeld" wrote in message om... (Gregory L. Hansen) wrote in message ... In article , John Schoenfeld wrote: POSTULATES OF A MODIFIED CLASSICAL PHYSICS Inertia law: Mass is a scalar velocity field: Scalar form: m(v) = m0 + int(0,v) (dm/dv) . dv Vector form: m(v) = m0 + intP(0,v) grad_v(m) . dv 1st Law of Motion: The momentum of a body remains invariant unless otherwise acted on by a Force. Scalar form: p = m(v) v Vector form: p = m(v) v 2nd Law of Motion: Force is the 1st time derivative of momentum. Scalar form: F = (m + v dm/dv) a Vector form: F = (m + v . grad_v(m))a 3rd Law of motion: Interacting bodies conserve net momentum through equal and opposing Forces. How are these modified postulates? They look like Newton's postulates to me, except you've specialized them to a mass that varies with velocity in an unspecified way (what's dm/dv?). It's still p=mv, F=dp/dt, and conservation of momentum. No, it's p = m(v)v. The different is important. Then please explain this important difference between p = mv and p = m(v)v Franz |
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