# Talk:Classical mechanics

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## More General Methods

The article states that:

"More abstract and general methods include Lagrangian mechanics and Hamiltonian mechanics."

I think that is not quite true. Lagrangian Mechanics as well as Hamiltonian Mechanics can both be derived from Newtonian Mechanics. So how can they be more general? Surely they are often easier to apply but that does not mean that they are more general. —Preceding unsigned comment added by 137.226.216.88 (talk) 16:29, 8 August 2009 (UTC)

Done Okay, I removed it

-Charlie- (talk) 15:12, 7 February 2018 (UTC)

## Errors in Domain of Validity DIagram

The current version of the Domain of Validity diagram is in error in its axis labelling:

1. The vertical axis should be in meters, not m/s. Also it's not clear from the article how the dividing line of 1 nm arises as the boundary between classical and quantum mechanics (although I would agree with that length).

2. The horizontal axis classifies speeds in terms of 3 x 10^9 m/s, which I think is supposed to be the speed of light. But the exponent is wrong, c is approx, equal to 3 x 10^8 m/s (i.e. 300 million m/s.

I'd fix this myself but am not sure how to.

I just came here to complain about the same thing Tweesdad mentions in his item #1 above. I agree that #2 is a problem also. This is an SVG diagram, and I have InkScape installed on my computer, so I may take a whack at it this weekend. I'm a complete novice at using it, so I can't promise anything yet!  :) CosineKitty (talk) 20:16, 28 January 2010 (UTC)
Follow-up: for the sake of clarity, what would be the limiting measure for the size at which quantum effects are "important"? Would it be 10−9 m, or some other value? The Planck length seems far too small to be what we are talking about, so I wonder if there is some other more readily understood significance to the size scale we are talking about, such as the approximate size of a typical atom, etc. Also, I think I would like the horizontal axis to refer to "c ≈ 3 ×108 m/s", not just the numeric value, so someone who looks at the diagram without reading the caption will better understand its significance. CosineKitty (talk) 20:23, 28 January 2010 (UTC)
I have corrected the mistakes in the diagram. I was able to do this without using InkScape. I just edited the file using Notepad, searched through the XML gibberish for the mistakes and corrected them. I didn't bother with adding "c ≈ "; I just corrected the unit mistake ("m/s" to "m" on the vertical axis) and the exponent for the speed of light. I didn't want to spend half my morning fiddling with alignment, etc! CosineKitty (talk) 14:49, 31 January 2010 (UTC)
I still see 3 x 10^9 m/s. In the article view as well as the source of the svg file dated 2010-01-31. −Woodstone (talk) 15:13, 31 January 2010 (UTC)
It looks OK here, but I had to reload the page - depending on your browser it can be cached, both here and on the image page.--JohnBlackburnewordsdeeds 15:23, 31 January 2010 (UTC)
Yes, you may need to force reload bypassing the browser cache. On most browsers you can do this by pressing Ctrl+F5. Alternatively, you can tell your browser to flush its cache and then reload. CosineKitty (talk) 17:21, 31 January 2010 (UTC)

## Impulse Turbine Design

Having come to know about turbine specific speeds, efficiency etc, how do we design the blade profile? Are there any set formulas to use? Where can I get them? Can someone help? —Preceding unsigned comment added by F.cuben (talkcontribs) 09:55, 2 March 2010 (UTC)

## Impulse Turbine Design

02 March 2010

Having come to know about turbine specific speeds, efficiency etc, how do we design the blade profile? Are there any set formulas to use? Where can I get them? Can someone help?

Regards

Felix T Ncube +27 83 950 6928 —Preceding unsigned comment added by F.cuben (talkcontribs) 09:56, 2 March 2010 (UTC)

## Impulse Turbine Design

F.cuben (talk) 09:58, 2 March 2010 (UTC)Cite error: There are `<ref>` tags on this page without content in them (see the help page). 02 March 2010

Having come to know about turbine specific speeds, efficiency etc, how do we design the blade profile? Are there any set formulas to use? Where can I get them? Can someone help?

Regards

Felix T Ncube +27 83 950 6928

First, the Classical mechanics should be the overarching article: the one article that set the stage for any other article in the navigation panel. Every other article should be mentioned to some extent in it. And when I say mention I mean not to include formulas and derivation etc. That type of content is for specific articles at lower levels in the hierarchy.

So I don't know how this would work, but I suppose I can suggest the first tasks and people can, like always, collaborate with the best of their abilities and time.

The first two tasks would be:

1. Work on the Classical mechanics article by: Merging into it Kinematics, Analytical dynamics, and Dynamics (mechanics). (Even statics should be merged, but lets do that later). Why merge these articles? First, those articles should not develop the whole mathematical formulation of every topic they deal with. For example, the article Kinematics currently is explaining way too much; it is going into details of rectilinear motion, circular motion, etc... There is no need for that. Those topics have their own article where formulations and examples can be developed. Kinematics should only be mentioned and explained to a certain extent (which we will see how much is too much) in the classical mechanics article. So, if those three articles are not going to have formulations, then let's just merge them into classical mechanics.
2. (This will be a little bit more controversial) To use the Non-inertial reference frame Reference frame article as the second level of the hierarchy (Inertial reference frame would be at the same hierarchical level). Merge Inertial reference frame, Non-inertial reference frame, and Rotating reference frame into that article. In this sense, the article on Fictitious force should be merged into it as well. Why? Because fictitious force is not a topic, it is a consequence of non-inertial frames, it does not need a whole article. But what about all the types of fictitious forces etc that are being developed in that article, you would ask? Well, the way I suggest it should be is to mention fictitious forces in the non-inertial frames article and then each type of fictitious force would be developed with formulations and examples in each motion article where it appears circular motion, or its own article, e.g. Coriolis force.

There, those are the first two tasks. Hopefully I was persuasive enough. Any comments or other suggestions are more than welcome. At the end the important things is to do something that improves all these articles. Let me know what you guys think. sanpaz (talk) 16:59, 4 June 2010 (UTC)

Please start an outline of the hierarchy you have in mind and wikilink in the current article(s) that is/are the closest fit for each. Right here would be fine. For example, I put this together to start sorting out all the bicycle drivetrain system article that have sprouted up over the years. -AndrewDressel (talk) 21:23, 4 June 2010 (UTC)
I agree with AndrewDressel. In this situation, the outline would be a useful organizational structure, and it would give us an overview to follow throughout this process. In fact it might help to give us a common vocabulary as we endeavor to solve this situation. Also, based on the above rationale, I think the idea of merging Kinematics, Analytical dynamics, and Dynamics (mechanics) into Classical mechanics is a very good first step. ----Steve Quinn (formerly Ti-30X) (talk) 02:37, 5 June 2010 (UTC)
I agree. I road map is necessary. I am working on it right now. I will post it later today. sanpaz (talk) 19:15, 7 June 2010 (UTC)

### Classical mechanics map

Below is the map for classical mechanics. I hope this is what AndrewDressel meant. The map is not suppose to be a tree structure nor a table of contents. The indentations mean a lower level (It does not mean for example that the article on rectilinear motion goes under the article Frame of reference.) Each line with a numeral refers to an actual article. The bullet points are what the article should contain. One thing that this map does not address is where to include Lagrangian and Hamiltonian formulations for the types of motions. As I am not familiar with these formulations maybe some of you guys may have some suggestions. All these articles are based on Vectorial mechanics (Newtonian formulation). sanpaz (talk) 02:36, 8 June 2010 (UTC)

1. Classical mechanics
• Definition of classical mechanics, kinematics, dynamics (mechanics), Analytical dynamics statics, continuum mechanics etc (Branches in general).
• Merge kinematics, dynamics, analytical dynamics and statics.
• Description of the topics (motions etc) that are included in those branches with wikilinks to their main articles . Make clear reference to particle mechanics, rigid body mechanics, and deformable body mechanics.
• Mention of inertial and non-inertial reference frames.
• Description of the vectorial and analytical formulations (Hamiltonian and Lagrangian)
• Description of laws that are the foundation of classical mechanics.
• History of classical mechanics.
• Relation with quantum mechanics and relativity.
2. Motion
• Mechanics is about motion of objects, assumed either as a particle or a rigid or deformable body. Therefore, motion should be second in the hierarchy. This implies that all other articles are classified or organized according to motion as it is seen in the levels below (Rectilinear motion and curvilinear motion for a particle, rigid body mechanics)
• In this article the next concepts should be defined: Displacement_(vector), velocity, speed, acceleration, Jerk_(physics), jounce?, Crackle_(physics)? (I don't know much about jounce and crackle so I don't know if it is relevant to classical mechanics. I think not) This brings the question: should we merge these concepts into motion? My take is yes, because all these concepts will reappear in rectilinear and curvilinear motion of particles, and kinematics and dynamics of rigid bodies, so the formulation for each concept in these different types of motion will be addressed in those articles.
• The next question is: Merge the laws of motion (Newton's and Euler's)? I think not. Just mention them and link to them.
3. Frame of reference (This changes my view of task #2 in the discussion above)
1. Newton's laws of motion for a particle
2. Euler's laws of motion for rigid bodies and deformable bodies
3. Rectilinear motion (particle) (kinematics and dynamics)
4. Curvilinear motion (particle) (Kinematics and dynamics)
5. Rigid body mechanics (kinematics and dynamics)

### Classical mechanics map continued

• For #1 - Classical mechanics appears to be a general structure that will work. For #2 yes, I think merging these concepts into motion will work. If jounce, jerk, and crackle have no place else to go I don't see a problem with at least giving them a brief description with a link. A caveat can even be placed in the description (just an idea). With an overview such as this the same information will not be re-hashed over and over.
For #3 formulations from any motion will be addressed in other articles, I agree, for now. Merge Inertial reference frame, Non-inertial reference frame, and Rotating reference frame articles into this article, and the title is good and I think we should stick with "Frame of reference". I agree with sticking with definitions and descriptions without formulation. And of course there will be articles that stand on their own that will need links in this article.
For "Newton's laws of motion for a particle" are you saying this should be a single article? It can't be covered in "Newton's laws of motion? " I mean maybe it can't. Also while we are on the subject check out "Point particle", and see if you think any of this article fits here, into this hierarchy. I am thinking the overall idea for point particle somehow emerges from Newton's descriptions, yet it was also adopted by Quantum mechanics.
Overall the hierarchical structure works for me and will be very helpful. I say begin to proceed, or proceed to begin. The more articles that can be merged the better. ----Steve Quinn (formerly Ti-30X) (talk) 04:05, 8 June 2010 (UTC)
I am saying that the current Newton's laws of motion article is already refering to the laws of motion for an object modeled as a particle (the object or body is small compared to the motion it is experiencing). Then the Euler's laws of motion would be describing the motion for rigid bodies.
I think the article Point particle can be part of the hierarchy (being included in the navigation panel under Fundamental concepts. The first paragraph of that article is general enough for all fields of physics. However, the rest of the article is more bias towards quantum mechanics and particle physics. So perhaps that article needs more description of its use in classical mechanics. sanpaz (talk) 14:13, 8 June 2010 (UTC)
I will try this week to give task #1 a go. I am not too sure how to proceed later with Task #2. Specially with the fact that those articles have several editors that may not be aware of this discussion, and may not be in instant agreement with merging those three articles. Perhaps the best protocol is to suggest the merge in those articles, refer the editors to this talk page so they can see the ideas spinning all these mergers, and then hear suggestions then incorporate them and hope it gets the go ahead without too much resistance.
We can continue in this page the discussion of the general map as the articles evolve, merge, etc. sanpaz (talk) 14:23, 8 June 2010 (UTC)
That the point particle article needs more description of its use in classical mechanics, is a good idea, and I will look into this. Regarding task # 1 that will get the ball rolling. Regarding #2 it is probably would be best to leave a message on the relevant talk pages, and then direct the conversation over here, so it can be kept in one place. Hopefully, this will make sense to those other editors.----Steve Quinn (formerly Ti-30X) (talk) 05:34, 9 June 2010 (UTC)
Also the following articles: Displacement (vector), Velocity, Speed, Acceleration, and Jerk_(physics), are all relatively small articles, so this would work well as one article, even though it may come across as a novel idea. However, each of these will have their own redirect page if the merge takes place, and they can each be redireted to the relevant section. I am also noticing the articles in curviliear motion seem to go together well. ----Steve Quinn (formerly Ti-30X) (talk) 05:40, 9 June 2010 (UTC)
I just added a blurb about the discussion here on the talk page of the Speed article. I left a link for this section where the discussion is taking place. Hopefully this helps. ----Steve Quinn (formerly Ti-30X) (talk) 06:00, 9 June 2010 (UTC)
I am working on the Classical Mechanics article. With the World Cup happening I haven't had much time to do anything else but watch it :). I will try to post something by Friday. sanpaz (talk) 01:45, 15 June 2010 (UTC)

### Classical mechanics branches

I believe Relativistic Mechanics is NOT a branch of Classical Mechanics. Please, review this.George Rodney Maruri Game (talk) 21:30, 28 September 2010 (UTC)

## Misuse of sources

A request for comments has been filed concerning the conduct of Jagged 85 (talk · contribs). Jagged 85 is one of the main contributors to Wikipedia (over 67,000 edits, he's ranked 198 in the number of edits), and practically all of his edits have to do with Islamic science, technology and philosophy. This editor has persistently misused sources here over several years. Please see, Wikipedia:Requests for comment/Jagged 85/Evidence. This editor's contributions are always well provided with citations, but examination of these sources often reveals either a blatant misrepresentation of those sources or a selective interpretation, going beyond any reasonable interpretation of the authors' intent. I searched the page history, and found 15 edits by Jagged 85 (for example, see this edit). Tobby72 (talk) 22:32, 4 June 2010 (UTC)

A lump of the history section still looks very much like a Jagged contribution, and in view of the lack of discussion here I've commented it out. If someone wants to support inclusion of this info, explicit new sourcing is needed. . . dave souza, talk 18:20, 31 March 2011 (UTC)

## Relationship with Newtonian physics

How does classical mechanics relate to Newtonian Physics? Are they synonymous, or is one outdated? When Googling "Newtonian Physics," no Wikipedia results appear. We should address the concept somewhere on Wikipedia. — Preceding unsigned comment added by Rob Hurt (talkcontribs) 23:54, 8 July 2012 (UTC)

Classical mechanics is Newtonian physics. The newtonian physics articles is redirected to the Classical Mechanics article. Perhaps the Classical mechanics article should have this term explained (if it has not already been done. I have not checked). There is already a reference in the Classical Mechanics article to the term Newtonian mechanics. sanpaz (talk) 17:55, 9 July 2012 (UTC)
There are also Lagrangian mechanics and Hamiltionian mechanics, so I would only call the old formulation with Newtons laws Newtonian physics.-Charlie- (talk) 15:26, 7 February 2018 (UTC)

## Varia

What's the pertinence of the "impetus" image to the present content of "History" section? I'd rather there could be an "inclined planes" experiment picture. Or nothing. ? Josh, linguist (talk) 13:52, 7 October 2013 (UTC)

I came across this article while tripping about the links, and found what was basically a non-description of CM as the lead. It spent the majority of time telling us what CM wasn't and how it failed, almost nothing on what it was and the astonishing effect it had on history. I hope I have addressed these issues.

As part of this edit I have removed an extensive note. Part of this described the term "classical" by comparing it to classical antiquity and saying it is not the same thing. However. I believe that is not true, and that the "classical" in the term may be a direct reference to classical antiquity. Certainly that is always they way I took it to mean, but I am by no means sure of this, so I'm turning here for comments.

Basically the classical world had two key concepts guiding their development of physics. One was that the world was an illusion, that we cannot judge our senses, and should rely as much as possible on "pure" ideas. Hand in hand with this was the concept that geometry was the "real" mathematics, and everything else was, to more or lesser degrees, less trustworthy. Certainly numbers were considered highly suspect - that's what accountants did. Euclidean space existed outside reality, and was perfect, by any definition of that term.

Certainly in the later respect, classical mechanics is classical, as it treats space and time as abstract ideas, non-physical. Relativity turns that on it's head, which is why I had always been told that relativity is not classical - that specific point. This is suggested in The Metaphysics of Modern Science, but he does not come out and say that specifically (at least in the first 80 pages or so).

Maury Markowitz (talk) 16:39, 21 January 2014 (UTC)

I think this needs a lot more work. I've reverted per WP:BRD (except for two edits) in order to discuss this more.
I disagree that lead spent the majority of time defining Classical Mechanics in terms of what it's not and how it failed. The WP:LEDE really should attempt to comment on the "astonishing effect [the scientific revolution] had on history". The former lede was much better focused and more WP:NPOV.
I'm not really sure I understand what the concern about classical antiquity clarification is?
"Basically the classical world had two key concepts guiding their development of physics..." While I certainly welcome elaboration here on the talk page, I think some of these broad strokes may have made it into the article edits and that would seem to be WP:OR.
I believe the article discusses whether or not relativity is considered part of "classical mechanics"...
I think you have some interesting ideas to improve the article but I'd like to see them incorporated into the current material rather than supplanting it.—Machine Elf 1735 03:10, 25 January 2014 (UTC)

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## 'Classical Mechanics' byline "F = m a" issues

Actually, F = dp/dt ( Newtonian Force Equation ) Then dp/dt = m * a, yet only when the mass is constant. The mass isn't constant when dealing with many systems, such as rockets when considering the rocket to be the material inside the hard boundary of the rocket, material traveling at approximately the same velocity.

Wikipedia Classical Mechanics articles have a CM tag box on the right, with "F = m a" in it. I think it's silly that the formula used to symbolize classical mechanics is not accurate in many cases. However, I can't come up with a better one, so I am not proposing any changes here. Perhaps someone else can think of a better formula or other byline.

I bring this up because I would hate for people to be misguided, especially if they are trying to understand rocket dynamics. Trying-bold (talk) 23:44, 6 April 2019 (UTC)

## Reference to article with NPOV issues

The list of formulations makes a reference to an article with clear neutrality issues. That list should only point to notable formulations that are on par in their fundamental impact with the Lagrangian or Hamilton-Jacobi formulations (as some examples). I suggest the removal of the reference to the Udwadia-Kalaba equation for lack of notability. Reading the linked article, it looks like an attempted promotional push. As is well known, there is no unique formulation of analytical mechanics and the list should only point of especially notable formulations such as the Hamilton-Jacobi equation. The reference to the little-known Udwadia-Kalaba equation in the same vein as the other substantially more notable ones is inappropriate.

- V madhu (talk) 11:38, 2 December 2019 (UTC)