Talk:Classical mechanics

Gareth, I like some of what you've done, but I'm a bit disappointed with the resulting formatting changes. In previous versions, each concept had a separate, dilineated section with information presented in a concise, organized manner. This was useful for quick reference. Your version is more precise and reads better than earlier versions, but is less useful as a quick reference. My recommendation is to add a separate page titled "Equations of Classical Mechanics" or "Summary of Classical Mechanics", which will basically be a table of the various important equations in classical mechanics.

The page should start with definition equations for the various key parameters (eg. velocity, acceleration, force, work, kinetic energy, momentum, angular momentum, etc...). This section could then be followed by a listing of other useful equations, like x=1/2at²+v₀t+x₀. What do you think?

--Matt Stoker

Thanks for the praise. The "Equations..." page sounds like a really good idea - GWO

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Personally, I would prefer defining force at least initially as, F = m*a, however, if the consensus is that F=d(m*v)/dt is more precise,

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I phrased it like that for a few reasons. Its a more literal "translation" of what Newton said, you do need it for some problems (the pendulum drop sand, rocket burning fuel...) and (last and least) it fits with the concepts of relativistic mechanics (4-momenta and all that) better -- GWO

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would it be preferable to first define momentum as p=m*v and then define force as F=dp/dt?

--Matt Stoker

Yes, it would be better. That way you can keep the same definition of force in relativity.

Could be. Weigh up the addition of some more notation, with the simplification of some of the equations. Would it obscure the logical flow behind F=d(m*v)/dt=m*dv/dt=m*a ? I guess the notation thing is the age-old problem of mathematical writingGWO

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Just did a major overhaul of the classical mechanics equations. Mostly I added a few equations here and there, made vector quantities bold, and changed the format to be more friendly with bold vector quantities.

Moved the request: Someone please add the equations for gravitational, electric, and magnetic forces

to this page, and responding. Gravitational may be appropriate, but electrical and magnetic force definitions belong with articles on electricity and magnetism (believe me, they're another whole ball game).

Final note: physicists divide physics in to classical and quantum mechanics. Einstein's relativity is actually lumped in with classical.

I'm not sure it's so cut and dried. I know there are quantum mechanical approximations that are based on "classical mechanics" and then if necessary relativistic corrections are tacked on.--Matt Stoker

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I've gutted the article and re-written major parts of it. It's still far from complete, but I'm structuring it after quantum mechanics, which I think has a very nice layout. Some of the removed material probably ought to be stuck back in, either here or in a separate article.

Comments are welcome. Hope I haven't ruffled any feathers :-P

Some changes, with reasons:

• Removed the description of SI units. They ought to go into the respective nodes for force, mass, and so forth; in my opinion they are distractions from the presentation of the theory.
• Removed most of the examples, but I want to put them back in somewhere. Some of the examples were rather disorganized, e.g. discussing the effects of gravity without having introduced gravitation. Also, Newton's law of gravitation is quite independent of the formal structure of classical mechanics, and that wasn't coming through properly.

Ultimately, I think we'll want to have links to the important sub-topics of classical mechanics: composite objects, inertial and non-inertial reference frames, oscillations, and so forth. -- CYD