Talk:Frame of reference

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A reference frame is a "box of rocks"?.....I deleted this....but it's still a mess. rsl

Ugh. Reads as a snobbish essay, not an encyclopedia entry. I don't even know where to start with fixing this one... -- Jake 06:21, 26 Sep 2003 (UTC)

I suggest ignoring it completely and rewriting it from scratch, not letting it hang around our necks like a dead albatross. It doesn't say anywhere that edits have to be incremental. If someone who knows physics would just boldly replace this with something less inscrutable? I don't see incremental edits ever salvaging this. In particular, the procedural flavour has to go. As a reader I don't care about "constructing" a frame of reference, I just want to know what it is. I don't expect a guided tour of a car factory when I ask what a car is, after all. JRM 16:54, 2004 Dec 3 (UTC)

I (different I) got a few sentences in, noticed that it was suggested that a moving car has to be accelerating, and stopped reading.

Contents

[edit] rewrite finished

I did the major rewrite, (I wasn't signed in that's why it just has my ip). I mentioned on the needs attention page some things that I think still need to be done. For instance the equations look horrible because I don't know latex. Also I think the application of reference frames in special relativity should get more attention. I don't remember a lot of the conventions, and won't have time to look them up until the semester is over. I don't know if it's exactly what we wanted, but at least it's not an essay anymore, and might help someone if they came here looking for how to work some problem. Let me know what you think! :) Starfoxy

The railroad car analogy is well-known for an example as an inertial frame of reference, since the train attempts to operate at a constant speed; hence the railroad car (the frame) is not accelerated. Is that what the requesters were looking for when they asked for a rewrite? That is a single sentence. Ancheta Wis 02:20, 3 Jan 2005 (UTC)

I added some more information on measurements in accelerating reference frames and tweaked the formatting to hopefully make it a bit easier to read. I think I also addressed the point above about a constant-velocity frame being inertial, and I think the LaTeX looks a little better, although experts are of course welcome to come in and fix it :-). I'm not too sure I like the organization, but I couldn't think of a way to fix it, so I left it as is. Steven Luo 05:39, 9 Jan 2005 (UTC)

I revised the paragraph about the dependency of observations on the frame of reference and added a link to the principle of relativity.StuTheSheep 16:33, Mar 1, 2005 (UTC)


I think the story about 'Alfred and Betsy' is very unlike encyclopedic style. I think there is no need for an article on 'frame of reference', I think a dictionary-style description is sufficient.

Frame of reference caution is equally important in newtonian dynamics and in special relativity. But the transformations of special relativity are counterintuitive, so in special relativity it is harder to switch mentally from the perspective of one frame of reference to the perspective of another frame. --Cleon Teunissen 17:49, 2 Mar 2005 (UTC)

i have trouble figuring this out: i really dont know what the frames of refrence is and what would it be in this sentence: The sun is over the horizon??


Clarified an ambiguity in my previous revision. StuTheSheep 05:49, Mar 3, 2005 (UTC)

[edit] from pages needing attention

  • Frame of reference - what we have now is inscrutable and probably unsalvageable by incremental edits. Could a student of physics do this anew, and do it right? JRM 16:56, 2004 Dec 3 (UTC)
    • I rewrote the article, but it's still not good. My latex skills are sorely lacking so the equations look bad, and I didn't cover special reletivity very well because it's been awhile, and I don't remember much about the conventions. If anyone could help wikify it, and help me make the equations look better then that'd be great. Starfoxy 12/9/04

[edit] The formula for the coriolis force does not describe a transformation

The current article contains a principal flaw. In the current article the following formula is called a transformation:

\vec F'_\mathrm{coriolis} = -2m\vec\omega \times \vec v'

This is incorrect. The formula contains the term \vec\omega .
\vec\omega is the rotation of the system with respect to an inertial frame of reference. That is, the rotation of the system with respect to a non-rotating frame. Whether a system is rotating or not can be measured in several ways.

In the transformations of special relativity there is symmetry, neither frame that is involved in the transformation is considered "the non-moving frame". In special relativity there is no concept of "the non-moving frame". Any relative velocity can be inserted in the transformation; in the transformed situation the laws of motion once again hold good.

The formula for the coriolis force involves a non-rotating frame and a rotating frame. So it is not a transformation, analogous to the transformations of special relativity. The formula for the coriolis force is an algorithm. The algorithm creates for each rotating frame a "law of motion" that is valid in that frame only. If a system is rotating with an angular velocity of 1 rad per second, then the special, additional "law of motion" for the co-rotating reference frame of that system is the formula for the coriolis force with that particular rotation rate inserted.

General relativity is magnificent, and it certainly is correct, as is shown by the fact that GPS technology takes several consequences of general relativity into account in order to achieve its level of accuracy. Contrary to what many people assume, general relativity does not extend the type of relativity of special relativity to accelerated motion. (Einstein did aim for that, initially, hence the name.) --Cleon Teunissen 21:28, 2 Mar 2005 (UTC)

Perhaps the most remarkable facet of general relativity was Einstein's ability to rectify the error in the longitude of perihelion of Mercury, which was found to be 43 arc seconds per century. With 415 orbits of Mercury per hundred years, 360 degrees per orbit, 60 arc minutes per degree and 60 arc seconds per arc minute, that enormous error is 43 parts in 537840000, or 0.0000079949427338985571917298824929347%. Magnificent work for someone working with a 3 significant figure sliderule and book of log tables. Of course tis was carried out about 100 years ago, and the initial observation of Mercury took place a century before that, so the telescopes 200 years ago were a miracle of optical precision, unequalled today even by HST. Der alte Hexenmeister 17:39, 9 July 2006 (UTC)

[edit] PSSC Physics Educational Film Series

There also exists an excellent educational film by the Physical Science Study Committee in the 1950s titled Frames of Reference which explains the problem of the bias of personal perspective in studying problems in physics. (e.g. The earth appears to be stationary; the sun appears to move around the earth. The earth appears to be flat. Time appears to pass in fixed intervals, rather than relative to the fixed transmission of light.)

[edit] Example image

Not to insult the person who made the image for the Example section, but is there something more professional-looking that someone can make to replace it? Super Jedi Droid 04:01, 12 November 2006 (UTC)

[edit] Edit to first paragraph and Overview

I decided to edit the first paragraph to remove any reference to an inertial reference frame being one which does not rotate nor accelerate. These terms are relative and therefore meaningless. It is much better to say that Newton's first law is valid in inertial reference frames. I also decided that the overview was in need of a complete re-write and so I decided to dedicate some time to this effect. I hope that my changes are a considerable improvement but I do not pretend that they are in any way complete. This article needs some serious looking over by a professional in this field, which I am not. I hope that we might some day soon reach an article which holds some worth. 130.88.186.123 09:24, 3 May 2007 (UTC)

I'm not going to touch the overveiw, this article's a mess, but i do have to point out that Newton's first law can be applied to non-inertial referecnce frames. A inertial reference frame is moving at a constant velocity. Objects on the Earth are not in an inertial frame due to the constant acceleration of gravity. However for basic physics the car traveling at thirty m/s or whatever is assumed to be inertial as the motion is perpendicular to the acceleration. All Newtonian mathematics can be applied to frames whose motion is perpendicular to the aceleration and less than .1c SilverDream 02:44, 8 June 2007 (UTC)

[edit] Difference between reference frame and coordinate system

The difference is not explained. I use the two expressions as "synonyms". Physicists tend to use the expression "reference frame", rather than "coordinate system", probably because Newton used the first rather than the second, but I cannot see the difference. In physics, you always need a coordinate system (with axes and units) to define any quantity. This coordinate system can be inertial or not inertial... Indeed, a coordinate system is a system of reference...

Paolo.dL 13:02, 24 August 2007 (UTC)