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Re: [Phys-L] strange things in chem book

Interesting thing to say, but perhaps not quite applicable in the case of gravity, where the shortcomings of both of these models are well-understood.

General Relativity has a limited range of applicability: It is not expected to necessarily give the right answers for very small-scale objects, where we would need some sort of quantum field theory. Newtonian gravity has that shortcoming and more: It also gives the wrong answers whenever the gravitational field is large, such as in the neighborhood of a large mass (star, black hole). The greater "region of validity" makes GR preferable, if one is willing to take the time to do the math. Of course, the simpler math of Newtonian gravity makes it preferable in its region of validity.

Ken Caviness
Physics @ SAU

-----Original Message-----
From: Phys-l [mailto:phys-l-bounces@phys-l.org] On Behalf Of jbellina
Sent: Monday, 17 September 2012 9:41 AM
To: Phys-L@Phys-L.org
Subject: Re: [Phys-L] strange things in chem book

Indeed, you could make the point that models with known limits are more reliable than models whose limits are unknown. In that sense, Newton's Laws are more reliable than GR.


On Sep 16, 2012, at 8:35 PM, John Clement wrote:

But laws do not have to be universally true. A law is valid within a
range of application such as the ideal gas law. Herein lies the confusion.
People tend to think a law is "universal truth" when the word law is
merely an expression of the usage and derivation of the equation or priciple.
Should F_f= mu F_N be a law? Why not it is just as valid within its
range of application as Ohm's law or Newton's law of universal gravitation.

Joseph J. Bellina, Jr. Ph.D.
Emeritus Professor of Physics
Co-Director
Northern Indiana Science, Mathematics, and Engineering Collaborative
574-276-8294
inquirybellina@comcast.net




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