Talk:Lorentz force/Archive 3

This is an archive of past discussions about Lorentz force. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

Archive 1

Archive 2

Archive 3

Inconsistent use of tau

In the relativity section (Covariant form of the Lorentz force) tau is used for c times proper time, then used for proper time after. In the first equation

{\frac {dp^{\alpha }}{d\tau }}=qU_{\beta }F^{\alpha \beta }

is tau not the proper time? If the c is referring to ct as in the 4-position (ct,x,y,z) i.e. time component then surley this can be clarified?-- F = q(E + v × B) 09:54, 2 March 2012 (UTC)

It has been fixed, followed by other minor edits. F = q(E+v×B) ⇄ ∑_ic_i 07:56, 30 March 2012 (UTC)

Maxwell Stress Tensor T + Poynting flux S equation

This has been re-sectioned, section diverged. F = q(E+v×B) ⇄ ∑_ic_i 13:47, 2 April 2012 (UTC)

Sorry about no edit summary in the last edit [1] - didn't fill it in and clicked save too early. It is: Newton's law is not relevant - why talk about it? also remove statement about the potential form - same thing is already above in the article, make a few bits clearer. F = q(E+v×B) ⇄ ∑_ic_i 11:49, 2 April 2012 (UTC)

Well, the removal of info was explained... but it was easier to read before, so the revert is not guilty.

Why re-state the force (per unit volume) in another way?? why add another equation for the sake of it?? It doesn't add much and will the reader care? Again - it was certainly easier to read before, which is why I reverted the other edit also. Maschen (talk) 11:54, 2 April 2012 (UTC)

Why was the relativity section "certainly much easier to read than before"? It had the pointless repetition of re-stating the equation

\mathbf {F} =q\left[-\nabla \phi -{\frac {\partial \mathbf {A} }{\partial t}}+\mathbf {v} \times (\nabla \times \mathbf {A} )\right]

which is already in the section Lorentz force in terms of potentials , as I just said above already. Also I only explicitly stated the α = 2,3 components of the 4-momentum p^α correspond to the y and z components because readers can interpret that easier. Back-reverted.

Why is it such a problem to state an equation using different quantities? Stating a result in two ways is beneficial. Back-reverted.F = q(E+v×B) ⇄ ∑_ic_i 12:01, 2 April 2012 (UTC)

F=q(E+v×B), "why, why, why???" Fine, your edits to the relativity section are fine. For the subsection Continuous charge distribution, it was better to just link to the Maxwell stress tensor and not introduce a tensor equation here, with vector calculus operators right at the beginning of the article. Also there is a discrepancy in notation - the WP article uses σ, while the citation Electrodynamics, Griffiths and Gravitation, MTW use T. You are adding unnecessary material just for the sake of it: padding out the section with concepts which may be relevant for a textbook, but beyond the scope of the section. Isn't the Poynting vector S for EM waves anyway, will that not side-track readers. Reverted again. Maschen (talk) 12:10, 2 April 2012 (UTC)

And just becuase your user name happens to be the equation of this article - does not mean you dominate it. Maschen (talk) 12:13, 2 April 2012 (UTC)

Once again - your idiotic accusations (or just irritating joke remarks - because you are a joke at times) of me "dominating" the article is simply false. I'll not explain why again since you can see our fight on Wikipedia talk:WikiProject Physics, look for the boldface segment ("Lets try and be clear again:") I wrote there.

For one thing - you contradict yourself: WP is supposed to use the most common notation, and you state two authoritive works which use T instead of σ. Really, that means we have to change the main Maxwell tensor page to T from σ?

Another thing is that

\mathbf {f} =\nabla \cdot \mathbf {T} -{\dfrac {1}{c^{2}}}{\dfrac {\partial \mathbf {S} }{\partial t}}\,\!

is a vector equation (only a 1st order "tensor equation"), since the divergence of a tensor field is a vector field (remember its a contraction of indices between components and derivatives: increasing the order of the tensor field by 2 then reducing by 1, so a 2nd order tensor field T becomes a 1st order tensor field, aka a vector field). And the statement is not even complicated: "∇• denotes divergence" is on pages like Gauss' law, Gauss's law for magnetism, Gauss's law for gravity, Continuity equation etc. Its stated and linked, which is the normal and correct thing to do. What is the problem with that?

Now - lets be good apples =) (not rotten like before): just becuase you don't like the equation there, yet will presumably add it to one of

doesn't mean you remove it from where it belongs (i.e. in its own background and context - not buried in a formula-list). Again - stating a result in two different ways helps different people interpret what the equation says. It should be there, and this time when I add it back: please, leave it. Let other editors be involved and come here and decide whether or not to include it, and the consensus reached here will dominate the decision (don't look now - but you are the one who is dominating that decision, and the article for now). F = q(E+v×B) ⇄ ∑_ic_i 12:48, 2 April 2012 (UTC)

Oppose: Surely - for an article of this importance, if the equation is that important it would have been added a long time ago. Anyway see the edit summary for the rest. Reverted. Maschen (talk) 12:53, 2 April 2012 (UTC)

This is stupid Maschen (like you and your endless reverting): you paid NO attention to what was just said. Now I can't revert again because you have now pulled us into a weak edit war, no more than 3 reverts are allowed else a block is imposed (in spite of me trying to assemble a consensus and discussion here on the talk page). So happy that you are removed info, and contradict yourself by saying I did so "without explanation" (again you only had to read what was said). =( F = q(E+v×B) ⇄ ∑_ic_i 13:01, 2 April 2012 (UTC)

Get over yourself - it’s just one equation. Now the (your?) world will come to an end!? No. I repeat: you do not like to (even try) and understand anything that is told to you, which is why your edits are reverted. Maschen (talk) 13:07, 2 April 2012 (UTC))

On second thought - it does look a lot like a fluid mechanics equation (almost like the Navier-stokes equation) considering the dimensions are energy per unit time and there is a divergence of a stress-type tensor. I guess imagining flows of quantities including energy is not hard to interpret, it’s just the term "tensor" will switch people off. Maschen (talk) 13:22, 2 April 2012 (UTC)

Really Maschen, really??? You just found that out? ??

Interestingly, in some funny way - thats exactly what I did write (except for the connection to fluid mechanics, but it was close in terms of energy flux). Perhaps you didn't read the few lines what were there after all?? You simply reverted "by accident" ??(i.e. without thinking, suprise suprise)

F = q(E+v×B) ⇄ ∑_ic_i 13:28, 2 April 2012 (UTC)

Sure - we can't expect everyone to follow all of the mathematics. Some people will switch off even when they see a few mathematical symbols, or even a simple algebraic equation, never mind the vector calculus formalism.

By your argument about tensors: shall we delete ALL tensor equations on WP - so it switches people off, and thereby making the articles more understandable?? Obviously we can't do such a thing.

Clearly your logic to removal is: "its too early for tensors in the article, since the rest of the article is entirely vector calculus (except for the relativity section)". That is simply absurd; the reader doesn't read one section after the next. It really will not matter if the equation contains a tensor in the beginning, there just is no problem with it.

The solution to that petty problem is to produce a section on later in the article: "Fluid mechanics analogy", or words to that effect, maybe with the derivation in a show hide/box. Its in the same source quoted. Then people will probably complain that the section will not be any use, followed by (you'll never guess!!) annihilation. F = q(E+v×B) ⇄ ∑_ic_i 13:47, 2 April 2012 (UTC)

Not a bad plan - if you're up for it. If people dislike they can explain themselves here. What do you mean by "annihilation" though? Maschen (talk) 13:48, 2 April 2012 (UTC)

I meant the section (what else?). ~~Are you sure you would not revert if I did?~~ F = q(E+v×B) ⇄ ∑_ic_i 13:51, 2 April 2012 (UTC)

Quit being so sore. No I wouldn't. When you're ready - go for it. Maschen (talk) 13:52, 2 April 2012 (UTC)

Neither the derivation or equation are essential. ~~It might be done later when I get time, else for now~~ the article can do without. F = q(E+v×B) ⇄ ∑_ic_i 16:22, 2 April 2012 (UTC)

What was I thinking??? The derivation is already at the Maxwell stress tensor - hence not to be included in this article. A brief mention of the equation would be lead nicely to it though. F = q(E+v×B) ⇄ ∑_ic_i 17:17, 2 April 2012 (UTC)

Why not add it back to the article then ??? Maschen (talk) 17:18, 2 April 2012 (UTC)

Will do. Pleased to know you finally appreciate it. =) F = q(E+v×B) ⇄ ∑_ic_i 17:19, 2 April 2012 (UTC)

In case you couldn't tell that was a sarcastic reply. Reverted for reasons repeatedly discussed above. Maschen (talk) 17:25, 2 April 2012 (UTC)

As I say above: a stupid waste of time. How am I supposed to mind read what you mean?? I even stated you acted in good faith, said we agree to a result, and for good measures added the link and happy face in this edit summary [2]. You didn't care, just throw it back instead in this edit summary [3]. Forget it. F = q(E+v×B) ⇄ ∑_ic_i 17:31, 2 April 2012 (UTC)

You should be able to tell by the number of question marks, lunatic. Maschen (talk) 17:32, 2 April 2012 (UTC)

Still at it?...

User:F=q(E+v^B), you are very "energetic" on including energy equations, arn't you? Maschen (talk) 20:05, 15 April 2012 (UTC)

Maschen - for crying out loud leave them alone. F = q(E+v×B) ⇄ ∑_ic_i 20:06, 15 April 2012 (UTC)

Contradiction with Maxwell's equation article

This article states "The first derivation of the Lorentz force is commonly attributed to Oliver Heaviside in 1889,although other historians suggest an earlier origin in an 1865 paper by James Clerk Maxwell". However, the article on Maxwell's equations states

"Maxwell's equations are named after the Scottish physicist and mathematician James Clerk Maxwell, since in an early form they are all found in a four-part paper, "On Physical Lines of Force", which he published between 1861 and 1862. The mathematical form of the Lorentz force law also appeared in this paper."

Pointing this out so that other editors may be able to resolve. — Preceding unsigned comment added by Tpellman (talk • contribs) 11:24, 25 April 2012 (UTC)

The text in the Maxwell's equations article was written by an editor (now banned from wikipedia) with extremely strong and extremely unusual opinions about Maxwell's work, based on his own reading of the original papers rather than proper secondary sources like history books. The text in this article was written by me based on one source that lacks a thorough historical discussion of Maxwell's different papers. Neither is necessarily correct.

My understanding is that Maxwell had something superficially similar to the Lorentz force law in both of the 1861-2 and the 1865 paper. Beyond that, the situation is more complicated...Details about the physical meaning that Maxwell ascribed to that equation, and how similar it is to the physical meaning that the Lorentz Force Law came to acquire eventually, and whether the similarity is enough to say he was really talking about the same thing. I certainly hope you or someone else finds a history book that discusses the matter, and edits either or both articles accordingly. :-) --Steve (talk) 12:14, 25 April 2012 (UTC)

Controversy

perhaps a section should be added covering the recent dilemma between the lorenz force and relativity

http://www.sciencemag.org/content/336/6080/404.full

N1ugl (talk) 02:57, 27 April 2012 (UTC)

Force in function form

It seems recent edits suggest the desire to write the equation explicitly in function notation. I did that in the lead section.

To Alousybum: thanks for your good-faith edits! Although you wrote q instead of q for electric charge which could imply to a reader that charge is a vector, given the earlier statement in the article

"All boldface quantities are vectors."

when charge is a scalar of course. =) F = q(E+v×B) ⇄ ∑_ic_i 07:02, 27 May 2012 (UTC)

EMF

The difference between "the conductor moving relatively to the magnetic field" and "the magnetic field moving relatively to the conductor" needs to be explained in more clarity. — Preceding unsigned comment added by 94.197.127.240 (talk) 05:57, 20 May 2013 (UTC)

Which part of that section are you referring to? M∧Ŝc²ħε И_τlk 20:21, 20 May 2013 (UTC)