Talk:Classical mechanics

'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)

uoioioioioioioioioioioioioioioio.com.net.@gmail 47.17.255.96 (talk) 23:23, 17 May 2023 (UTC)

puzzling paragraph on inertial frames

the unreferenced paragraph starting with "A key concept of inertial frames is the method for identifying" makes at least two dubious claims. first that acceleration is involved in Einstein relativity. second that stellar fixed coordinates have some meaning in mechanics. absent citations I believe both claims are incorrect. I propose to delete or significantly modify the paragraph. Johnjbarton (talk) 21:53, 14 June 2023 (UTC)

I removed the incorrect relativity comment and added citations for Goldstein on inertial frames.

Resolved

Johnjbarton (talk) 18:08, 15 June 2023 (UTC)

Proposal to shorten Description and focus this article on overview.

The current "Description of the theory" is really a description of Newtonian mechanics. As presented it distorts the over all topic.

I think the overall topic would be better presented by lifting "Branches" to the spot where Description lives and expanding the subheadings to summary sections linking Main. The current "Description" material would shrink to a paragraph, with possible movement to subarticles. Johnjbarton (talk) 19:02, 4 January 2024 (UTC)

This article does rather seem to suffer from not having been written with an overall plan in mind. Like so many broad-scope articles, it has become a repository for every little thing that somebody wanted to say. I like the idea of elevating the "Branches" section and expanding with {{main}} and/or {{further}} links. XOR'easter (talk) 02:02, 5 January 2024 (UTC)

OK, I made a stab at doing something like that. Maybe "Description of the theory" can be tightened now. XOR'easter (talk) 02:36, 5 January 2024 (UTC)

What do you think about moving the Lagrangian, Hamiltonian and and Hamilton-Jacobi sections of Newton's laws of motion#Relation to other formulations of classical physics in to this article? The Newton's law section would be just the current top paragraph and a main link to classical mechanics. This article would get a summary of Newtonian mechanics and the three sections on analytical mechanics. Johnjbarton (talk) 03:13, 5 January 2024 (UTC)

I prefer those where they are, since they're specifically about the guises in which Newton's laws present themselves in the alternate formalisms, rather than how to do anything in those formalisms other than re-derive the Newtonian approach. XOR'easter (talk) 03:18, 5 January 2024 (UTC)

I added sections on Hamiltonian and Lagrangian mechanics, because I think it makes sense to have them; this article calls for high-level overviews, while the other zooms in to the granular details of a specific aspect. What the page needs next is, I believe, a careful condensation of the long kinematics passages and the Newtonian section, with an eye to removing tangents and overly textbook-like material. XOR'easter (talk) 04:34, 5 January 2024 (UTC)

yes, I think we are at fork in the road: the Branches content is short and the rest is too long while also repeating somewhat. Moving more into branches will make it harder to navigate. So my suggestion is to take both forks

• Leave Branches.
• Change the name of "Description of the theory" to "Comparison among branches of classical mechanics"
• Convert the remaining content up to Limitations into summary paragraphs matching the Branches organization. These summaries should focus on helping reader choose, not on explaining.

Johnjbarton (talk) 19:19, 5 January 2024 (UTC)

I changed the heading of "Description of the theory" and split it in two, since the first part was about kinematics and could apply more broadly than just the Newtonian formalism (e.g., we still use reference frames and coordinates in the Lagrangian method). XOR'easter (talk) 20:50, 5 January 2024 (UTC)