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Cat

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I like the picture of the cat — Preceding unsigned comment added by Owen Scieszka (talkcontribs) 16:15, 4 June 2022 (UTC)[reply]

Thanks. To keep the picture we had to fight a battle against other editors who thought it was inappropriate. --ChetvornoTALK 16:53, 4 June 2022 (UTC)[reply]
I like it, too. Out of Phase User (talk) 02:22, 5 June 2022 (UTC)[reply]
I like it too, however, I wonder if a cat lover might think that this cat has been mistreated. This image was cropped from a larger image
Cat and styrofoam – electrostatic charge (235112299)
. I like this image better, since it is clear that the cat is not being confined and is free to shake off the Styrofoam peanuts. Constant314 (talk) 02:33, 5 June 2022 (UTC)[reply]
Maybe crop it halfway more and put it in. The original is cropped pretty tight, just aesthetically. Out of Phase User (talk) 21:40, 5 June 2022 (UTC)[reply]
Support The cat is here to stay. Alexceltare2 (talk) 21:55, 4 February 2023 (UTC)[reply]
Maybe we should add an easier way to find the full image on the page, since replacing the image with a slightly less tightly cropped version seems redundant. KurthyWurthy (talk) 21:04, 31 August 2023 (UTC)[reply]
What is the name of the cat? Bonaparte Napoleão (talk) 20:29, 30 November 2024 (UTC)[reply]

orders of magnitude

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k = 9x10^9 N·m^2·C^−2 q1 = q2 = 1.6x10^-19 C q1 x q2 = 2.6^-38 C^2 q1 x q2 x k = 2.3x10^-28

G = 7x10⁻11 N·m^2·Kg^-2 m1 = 1.7x10^-27 Kg m2 = 9x10^-31 Kg m1 x m2 = 1.5x10^-57 m1 x m2 x G = 1.1x19^-67

(q1 x q2 x k)/(m1 x m2 x G) = 2.1x10^39 Pediadeep (talk) 01:05, 16 November 2023 (UTC)[reply]

What we need is a reference, a source that shows this calculation is valid. Otherwise its WP:Original research. Thanks! Johnjbarton (talk) 01:26, 16 November 2023 (UTC)[reply]
This comes without reference, like it was with the claim of 36 orders of magnitude as it was before.
This calculation is pure simple low level mathematics combining physical constants, Coulombs law, and the law of gravity. It is trivial and stated here just for reference on its own.
I can understand the objection, but finding an external reference for this is (about) like finding a reference for stating that a car travelling with 100 km/h will make 28 meters in a second.
Sorry.
If I can not convince the community, we have to delete the entire statement, including the numbers. Pediadeep (talk) 20:31, 16 November 2023 (UTC)[reply]
https://www.texasgateway.org/resource/231-four-fundamental-forces Says compared to strong force and electromagnetism is . Same on http://hyperphysics.phy-astr.gsu.edu/hbase/Forces/funfor.htm
https://www.huffpost.com/entry/myths-of-physics-2-gravit_b_5718233 says the comparison typically derived by comparing forces on an electron and proton don't make sense. Or rather the entire nature of the comparison is not sensible. Force is not an independent quantity that can be measured, it always depends upon the circumstances.
Gleick, James. Genius: The life and science of Richard Feynman. Vintage, 1993. On page 352 says but its not completely clear what setup that refers to. Johnjbarton (talk) 21:06, 16 November 2023 (UTC)[reply]
texasgateway compares against the strong force, what is only of limited help here because strong force is definitifely not a classic conservative force as can seen from their statement that it has a range of 10^-15 m as compared to the range of infinity for bothe gravitation and elecro(static).
hyperphysics website does not answer to me, so I can not reason about.
huffposts article is quite a strange reasoning IMHO, and can not be taken serious.
Both articles just STATE what they claim, without giving references or proofs.
The point is, that in classical physics, neglegting quantum physics and relativity, both, gravitation and coulomb, regard the respective forces to have a strict 1/r^2 dependency, and coulomb takes additional a factor of q1xq2, where gravition has a respective factor of m1xm2.
And it is general consensus that both laws hold true especially in distance ranges that are considered to be accessible by experiment, say, some millimeters to billions of kilometers (of course their is no experiment prooving the validity of coulomb to such big distances).
Both laws are tested and verified by experiment, as it is agreed by physical community and common sense.
Please note that I am talking about classical physics for particles in rest.
We could decorate this statements about relative strength of these forces, but that would actually blurr the meaning.
Take it this way:
You have an electron at rest and a proton at rest, separated by a distance of one meter, what would the actual force(s) be. How would you calculate these? How would you measure.
You could take electrons and positrons, protons or antiprotons or anything else. I think electron and proton is very telling, particular in this case.
Of course we should compare apples with apples and nothing else, and electrons are only very very little similar to protons, as we know, but both are considered to have rest mass and charge, and the values of these masses and charges are very good understood, measured, and documented. Pediadeep (talk) 17:24, 17 November 2023 (UTC)[reply]
I broadly agree with your reasoning. Johnjbarton (talk) 18:24, 17 November 2023 (UTC)[reply]
The math is simple but the implications are purely theoretical because we are talking about things which are mathematical concepts rather than reality. For example, an electron and a proton at rest are textbook ideas. Bill field pulse (talk) 20:04, 16 January 2024 (UTC)[reply]
I disagrgee with such statement.
An electron at rest is as much a textbook idea as is a car at rest. 2A02:B98:4736:AC7C:F537:BE3F:7366:C530 (talk) 17:51, 24 January 2024 (UTC)[reply]
Thank you for pointing out this issue 2A02. Do you agree that in an atom they cannot be at rest because the field from a Proton is actually a field made by quarks cycling at near the speed of light? So the most likely place for an electron to be at rest is in a surplus of electrons in say a metal ball which is at rest. Do you agree that the fields of all the other balanced electrons in all the atoms in the ball are in a constant state of motion due to electrons moving in their orbitals. What happens to your perfectly spread out surplus electrons as they sit in these volatile EM fields in all the atoms. surely they must react to all the vibrations and field changes all around them. I would argue strongly that you can have a large number of electrons which have a net charge which is perfectly at rest. But at the atomic level there is so much activity even in a cold hard metal ball that it is impossible to hold an individual electron still. Only for an infinitely short instant is an individual electron truly at rest. I would appreciate more from you regarding the condition you have in mind where a single electron is at rest. However, if you agree that only a large number of electrons can have a net charge which is at rest then yes we are on the same page. Bill field pulse (talk) 21:14, 24 January 2024 (UTC)[reply]

Any relation?

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In a recent edit a user named @Lekner added this ref:

  • Lekner, J. (2021). [DOI: https://doi.org/10.1063/9780735423350 Electrostatics of conducting cylinders and spheres]. Melville, NY: AIP Publishing. ISBN 978-0-7354-2335-0. {{cite book}}: Check |url= value (help)

Please be aware of Wikipedia's Conflict of interest policy. Johnjbarton (talk) 03:22, 17 June 2024 (UTC)[reply]

It also turns out that almost all of the contributions by @Lekner consist of additions of references to works by J. Lekner. Johnjbarton (talk) 03:25, 17 June 2024 (UTC)[reply]
All reverted. A warning was left on the user's talk page. Constant314 (talk) 04:24, 17 June 2024 (UTC)[reply]

Electrostatic Approximation

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I see the article says "a system that exhibits no significant time-varying magnetic fields". In practice, I guess that means no time-varying currents and no moving magnets.

That would allow DC currents. Also, DC currents charging capacitors does having a linearly increasing E-field. And I guess DC currents with moving dielectrics.

I'm not objecting. I just want to be sure we want to allow those cases. Constant314 (talk) 18:54, 15 January 2025 (UTC)[reply]