Talk:Newton's laws of motion

message: In fluid mechanics Newton second law is called the linear momentum equation.
Can anyone add this point to this wiki article.
I found this point in Fluid mechanics Frank M White 7th edition pg:140  — Preceding unsigned comment added by B.NIROSHAN (talk • contribs) 09:36, 26 February 2024 (UTC)
thread_title:  suggestion to add this sentence 

message: As was recently reported in Scientific American, the Motte translation of the First Law used in this article is incorrect. Also the "unless" in the paraphrase should be changed to "except insofar as". The original article pointing this out is Hoek 2023. 2001:468:C80:C105:81EA:C534:C0F0:2602 (talk) 15:59, 1 October 2023 (UTC)
replies: text: Does changing "unless" to "except insofar as" actually change the meaning, or is that a distinction without a difference? Maybe, but as a native English speaker, "except insofar as" just sounds to me like a longer way of saying the same thing. And reading the Hoek article, he presents what he calls his "strong reading" of the first law as something that has "never been clearly articulated or explicitly defended in print." Since we're here to provide the mainstream/consensus view before anything else, I'm wary of changing a prominent part of this article based on a single paper and a pop-science news item about it. Hoek's discussion of why the "weak statement" and "strong statement" aren't logically equivalent involves calling several previous exegeses of Newton wrong (pp. 63–64) and then getting deep into the weeds about the second law and what Newton meant by terminology that is obsolete now anyway. (The Scientific American story, although better than a lot of pop science, doesn't try to summarize all this, so it's not that great of a secondary reference for Hoek's argument.) This could all be interesting in the "History" section of the article, but when we are first introducing the laws, we should explain what they have come to be, rather than what was on Newton's mind in 1687, which didn't even include F = ma.  When I first tried accessing Hoek's paper via the SciAm story, I hit a paywall and had to resort to my university library, but there's an arXiv version that appears to be substantially identical. XOR'easter (talk) 16:57, 1 October 2023 (UTC)

text: For what it's worth, Cohen and Whitman's excellent 1999 translation of the Principia renders the first law as "Every body perseveres in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by forces impressed." Generally I think Cohen & Whitman is a better translation than Motte, but in this case I tend to agree with @XOR'easter that there's not a big difference in the meaning of the two English translations. I am neutral as to whether the translation in our article should be changed. CodeTalker (talk) 17:55, 1 October 2023 (UTC)

text: I support changing "unless" to "except insofar as".  These are Newton's laws.  Newton was the one who decided how to word them.  He wrote it in Latin, and it was translated incorrectly.  The most accurate translation should be used.  As far as if there's a big difference, I don't think that is relevant.  Newton said what he said, and it should be worded with the correct translation.  But, Science Alert just wrote an article that explains why there is a big difference, why it isn't symantics, and why it's scientifically important and relevant.  Rather than paraphrase it and not do it justice, I'd suggest reading the article. Darlingm (talk) 22:16, 19 January 2024 (UTC)
replies: text: That's not a new story. It's a repost of the same churnalism piece they posted last September. It just repeats Hoek and copies from the Scientific American item already discussed above. A pop-science fluff website like "Science Alert" is not a reliable source for a serious question about the history and philosophy of physics. XOR'easter (talk) 22:36, 19 January 2024 (UTC)
thread_title:  Statement of the First Law of Motion should be adapted/modified 

message: In the main text, it states, 'If the mass does not change with time, then the derivative acts only upon the velocity, and so the force equals the product of the mass and the time derivative of the velocity, which is the acceleration.' This implies that the equation F = dp/dt is applicable to variable mass systems. However, it is not. To see why, realize that if it did apply to variable mass systems, then the equation could be rewritten as F = vdm/dt + ma, which is not Galilei-invariant. This also contradicts the correct equation F = ma - udm/dt, where u is the velocity of the exhaust relative to the rocket. NameIchose (talk) 23:03, 28 January 2024 (UTC)
replies: text: I agree with Namelchose. Objects of variable mass, such as a rocket or a jet-engine aircraft, must be analysed in a slightly different way. My reference is Resnick and Halliday (1966) Physics, Section 9-7 “Systems of Variable Mass”. Dolphin (t) 23:40, 28 January 2024 (UTC)
replies: text: Press the link labeled "edit" ;-) Johnjbarton (talk) 00:04, 29 January 2024 (UTC)

text: Also see Variable-mass system. Dolphin (t) 23:54, 28 January 2024 (UTC)
thread_title:  The text erroneously implies that Newton's second law in the form F = dp/dt is valid for variable mass systems. 

message: — Assignment last updated by Ahlluhn (talk) 00:57, 31 May 2024 (UTC)
thread_title: Wiki Education assignment: 4A Wikipedia Assignment