From: Ste on 16 Jan 2010 01:17 On 16 Jan, 04:33, "preedmont" <nos...(a)spamless.com> wrote: > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > news:dd68ad12-0046-499a-9391-452eb70953a0(a)a6g2000yqm.googlegroups.com... > > > On 16 Jan, 02:00, jdawe <mrjd...(a)gmail.com> wrote: > > >> force = push + pull. > > > How do we distinguish push from pull? > > push = - pull > > now add pull to both sides > > push + pull = 0 > > therefore, force = 0 So I'll ask again, how does one *distinguish* between push and pull? How can one tell when one is measuring push, and how can one tell when one is measuring pull? Or are they really one and the same thing?
From: preedmont on 16 Jan 2010 09:59 "Ste" <ste_rose0(a)hotmail.com> wrote in message news:1b611c0f-beb2-4b2e-a017-7079c480809f(a)l30g2000yqb.googlegroups.com... > On 16 Jan, 04:33, "preedmont" <nos...(a)spamless.com> wrote: >> "Ste" <ste_ro...(a)hotmail.com> wrote in message >> >> news:dd68ad12-0046-499a-9391-452eb70953a0(a)a6g2000yqm.googlegroups.com... >> >> > On 16 Jan, 02:00, jdawe <mrjd...(a)gmail.com> wrote: >> >> >> force = push + pull. >> >> > How do we distinguish push from pull? >> >> push = - pull >> >> now add pull to both sides >> >> push + pull = 0 >> >> therefore, force = 0 > > So I'll ask again, how does one *distinguish* between push and pull? > How can one tell when one is measuring push, and how can one tell when > one is measuring pull? Or are they really one and the same thing? push = pull - ll + sh push = not pull not push = pull pull - ll = push - sh OR pull - push = ll - sh
From: Uncle Al on 16 Jan 2010 10:21 preedmont wrote: > > "Ste" <ste_rose0(a)hotmail.com> wrote in message > news:1b611c0f-beb2-4b2e-a017-7079c480809f(a)l30g2000yqb.googlegroups.com... > > On 16 Jan, 04:33, "preedmont" <nos...(a)spamless.com> wrote: > >> "Ste" <ste_ro...(a)hotmail.com> wrote in message > >> > >> news:dd68ad12-0046-499a-9391-452eb70953a0(a)a6g2000yqm.googlegroups.com... > >> > >> > On 16 Jan, 02:00, jdawe <mrjd...(a)gmail.com> wrote: > >> > >> >> force = push + pull. > >> > >> > How do we distinguish push from pull? > >> > >> push = - pull > >> > >> now add pull to both sides > >> > >> push + pull = 0 > >> > >> therefore, force = 0 > > > > So I'll ask again, how does one *distinguish* between push and pull? > > How can one tell when one is measuring push, and how can one tell when > > one is measuring pull? Or are they really one and the same thing? > > push = pull - ll + sh > > push = not pull > > not push = pull > > pull - ll = push - sh > > OR > > pull - push = ll - sh Fermat's Little theorem less its second harmonic. Brilliant! -- Uncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) http://www.mazepath.com/uncleal/qz4.htm
From: Rock Brentwood on 16 Jan 2010 14:57 On Jan 15, 8:00 pm, jdawe <mrjd...(a)gmail.com> wrote: > force = push + pull. > push = solid matter + potential energy > pull = fluid matter + kinetic energy The identifications Maxwell used early on in his 1861 and 1864 papers were: E is potential H is kinetic and that in an isotropic medium (in the frame of isotropy) the corresponding inductions would be governed by the analogue of a spring coefficient (kappa) and of a mass coefficient (mu) and, thus, would read: D = kappa E B = mu H. That's where the coefficients and their names ultimately arose. Today, his kappa (the dielectric coefficient) is treated synonymously as our epsilon (the permittivity), but this identification is wrong. It's only valid in parity-symmetric media. In frame of reference moving at a velocity of -G relative to the frame of isotropy, his relations read: D = kappa (E + G x B) B = mu (H - G x D) where () x () denotes the vector product. He DID, in fact, incorporate the G x B term in the definition of E, so that his field-potential equation actually read: E = -grad phi - d_t A + G x B instead of just E = -grad phi - d_t A. So, his E is equivalent to our (E + G x B). But, in his early papers he never explicitly called out B as a separate field (though he identified it as a separate field in the adjoining verbal language), so he only wrote B as the diglyph (mu H). Moreover, his H is different from our H by a factor of 4 pi. So our mu is off from his by 4 pi. We would equate mu = 4 pi (which is normalized nowadays to 4 pi Henri per 10000km) while he would have written mu = 1 for the equivalent ratio. [And note: he didn't use the letter names for the fields until around the 1870's, but separate letter names for the individual components. He didn't use vectors or quaternions. Rather, he used differential forms -- both in the 1860's AND in the treatise.] Because he failed to fully distinguish B from H early on, he also failed to do the proper analysis for the corresponding transformation law. So, instead of getting B = mu (H - G x D) he left out the -G x D term. Only Thomson noted it, later on in the 1880's, though Maxwell apparently made an allusion to it in the verbal language early on in his 1861 paper. Today, the equations would be written (as per Einstein & Laub in 1908-1909 and Minkowski in 1908) as: D + (1/c)^2 G x H = epsilon (E + G x B) B - (1/c)^2 G x E = mu (D - G x H). For a medium at an index of refraction of 1 (i.e. epsilon mu = 1/c^2), away from the Cherenkov threshold (where epsilon mu |G|^2 = 1) this is equivalent to the "stationary" equations D = epsilon E, B = mu H. For media with non-trivial indices of refraction (e.g. outer space, particularly in the earliest epochs of the universe) it is not. The vector G identifies a universal frame of reference -- namely, the one associated with the Big Bang metric and with the cosmic microwave background. Nowadays, Maxwell's formulation would be represented by a Routhian R = R(phi, A, E, H) rather than a Lagrangian L = L(phi, A, E, B), since he took E and H as the independent variables. So, for an isotropic potential-idependent Routhian R = R(E^2/2, E.B, B^2/2) (where ().() denotes scalar product), his coefficients could be DEFINED by: kappa = dR/d(E^2/2) mu = dR/d(B^2/2) along with a third coefficient, which he completely overlooked: lambda = dR/d(B.E). And his constitutive law for the isotropic frame would then read: D = kappa E + lambda H B = lambda E + mu H which, when solved in terms of (E,B) gives the "Lagrangian" form of the constitutive laws: D = epsilon E + theta B H = (1/mu) B - theta E where theta = mu lambda epsilon = kappa - lambda^2 mu So, in the presence of the parity-violating coefficient lambda (or theta), the dielectric coefficient kappa no longer coincides with the permittivity epsilon. So, his "spring coefficient" kappa is not strictly identical to what we presently call permittivity, though his "mass coefficient" mu accords with our permeability mu, up to a factor of 4 pi.
From: Sue... on 16 Jan 2010 15:26 On Jan 16, 2:57 pm, Rock Brentwood <markw...(a)yahoo.com> wrote: =========== [...] > For a medium at an index of refraction of 1 (i.e. epsilon mu = 1/c^2), > away from the Cherenkov threshold (where epsilon mu |G|^2 = 1) this is > equivalent to the "stationary" equations > D = epsilon E, B = mu H. > For media with non-trivial indices of refraction (e.g. outer space, > particularly in the earliest epochs of the universe) it is not. The > vector G identifies a universal frame of reference -- namely, the one > associated with the Big Bang metric and with the cosmic microwave > background. Elsewhere I have shown the equivalence of a serpent bite taken from Newton's falling apple and the disparity between oscillators at the top and bottom of Harvard tower. If anyone thinks you are being overly speculative, I will try to dig up the URL to these convincing calculations with some experimental support. :o) Sue... [...]
First
|
Prev
|
Next
|
Last
Pages: 1 2 3 4 5 Prev: Unification of the instrument Next: One word to correct the nonsense of QM |