Talk:Newton's laws of motion
|
|
| Contents |
Original format?
Wouldn't it be nice to include the laws as he first wrote them in addition to the way they are paraphrased in most modern textbooks? I'd put them in myself but I'm having a hard time finding them anywhere on the internet. Maybe somebody else would have better luck?
- Do you mean as Newton first wrote them in Philosophiae Naturalis Principia Mathematica i.e. in Latin ? I can't see much point in that myself. If you mean "as Newton would have written them if he had written them in English", then any English version is a translation, and I think we might as well show a modern translation rather than a less understandable version in 17th century English. Gandalf61 10:40, Dec 13, 2004 (UTC)
Vandalism
The version 09:42, 1 Nov 2004 Gandalf61 is the last good version. I don't know how to revert it back in place. Thanks. --Nicop 16:01, 8 Nov 2004 (UTC)
Eponyms
Took out laws of inertia as a synonym. It is very misleading. The first law is the law of inertia. The plural term is not standard usage in physics. -- Decumanus
Newton's second law of motion
Newton's second law states a proportion, not an equivalence between the force, F, and the proportional 'change of motion'. Since Newton defines 'motion' by the product of mass and velocity, mv (Def. 2), the second law reads 'force is proportional (not equal!) to delta(mv). Obviously the mass m then is not available as a constant of proportionality, since it is part of the term 'change of motion'that is proportional itself to the 'force'. It is clear, then, that Newton's law cannot be represented by the F = ma of textbooks. In fact this F = ma is a formula that stems not from Newton but from Leonhard Euler (Mechanica 1735), and can be traced back to Leibniz's Specimen Dynamicum of 1695. The true interpretation of Newton's law that for the first time takes into consideration the constant of proportionality between 'force' and 'change of motion'can be found in Ed Dellian, Die Newtonische Konstante, Philos. Nat. Vol. 22 Nr. 3 (1985) p. 400.
- Surely the constant of proportionality depends entirely on the units involved (and so is not part of the law itself) ? If mass is in kilos, acceleration is in metres per second^2 and force is in Newtons then the constant of proportionality is 1 (this is the definition of the Newton). OTOH if mass is in lbf, acceleration is in parsecs per fortnight^2 and force is in dynes, the the constant of proportionality will not be 1. The expression F=ma assumes that the quantities are measured in consistent units which will make the constant of proportionality equal to 1. Gandalf61 15:11, Mar 9, 2004 (UTC)
Newton's Fourth Law: "Don't sit under ripe apple trees"
Sorry, couldn't resist =) - Peter Perlsų 00:33, 2004 Apr 25 (UTC)
additional useful information
1.when a person of mass m climbs up a rope with acceleration a, the tension in the rope is
T= m(g+a)
-varun nehru
After the last adaptation of Newton's 1st law (thank to the author who tried the simplification), I have some comments: I thin, even if this is not usual, that one of the expression of the first law should explicitely make a reference to the "reference frame" as it really defines them.
I think also that it does not make sens to say that "dv/dt = 0"
Lastly, I regret somehow that in this article, we rather quickly come and use derivative, some kind of calculus that cold be mentionned but that should be avoided (IMHO) as most people will anyway have forgotten most of their calculus if the ever had learnt any. Thanks. --Nicop 21:08, 8 Dec 2004 (UTC)
"Strong form" of Newton's Third Law?
Has anyone ever heard of "strong form" of Newton's third law? I've never heard that term in my physics classes, and considering that it's obeyed so little fundamentally (only by gravity--a version (er, months ago, before I changed it) had electrostatic forces as satisfying the "strong form" but that isn't true), I'm not sure if it's, er, worth mentioning. Does anyone have a reference that I can look up, or simply take out the reference about "strong form"? (Er, I didn't want to take it out entirely because I wasn't sure....) novakyu 00:33, 9 Dec 2004 (UTC)