What is Classical Physics?

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Can someone please tell me what is Classical Physics?

Does Kinematics in One Dimension such as in Physics textbook is considered a "Classical Physics"?
 

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  • #2
berkeman
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Not QM and not Relativity, I would think. Non-relativistic kinematics of macro objects would certainly seem to qualify as Classical, IMO.
 
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Doc Al
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Does Kinematics in One Dimension such as in Physics textbook is considered a "Classical Physics"?
Sure, kinematics is part of "classical" physics. But note that homework problems belong in the Homework section.
 
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Mister T
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Classical physics excludes quantum physics. Depending on who you ask, it may or may not include Einstein's relativity.
 
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vanhees71
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Can someone please tell me what is Classical Physics?

Does Kinematics in One Dimension such as in Physics textbook is considered a "Classical Physics"?
That's not so easy to answer, because not everybody agrees on what's "classical physics". For me classical physics is everything which is not quantum physics, i.e., on a fundamental level classical physics consists of Newtonian mechanics, classical electrodynamics, and special as well as general relativity. Some people also call relativity "not classical" though.
 
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Mister T
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It's been said that general relativity is the jewel in the crown of classical physics.
 
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Delta2
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I am an old romantic of the end of the 19th century, in my opinion classical physics is all physics as they have been assembled up to the end of 19th century 1880-1900 and they don't include special or general relativity, and of course not anything quantum (quantum mechanics, quantum electrodynamics).
 
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Ibix
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In summary:
  • Anything that is not using special relativity, general relativity nor anything quantum is definitely classical.
  • Anything quantum is definitely non-classical.
  • Special and general relativity may be classical or not depending who is talking. Note that non-quantum electromagnetism falls into this bracket since it's an inherently relativistic theory.
 
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vanhees71
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I am an old romantic of the end of the 19th century, in my opinion classical physics is all physics as they have been assembled up to the end of 19th century 1880-1900 and they don't include special or general relativity, and of course not anything quantum (quantum mechanics, quantum electrodynamics).
So is classical electrodynamics (Maxwell's and the Maxwellian's version of it) then classical, because it was definitely discovered in the 19th century or is not not classical, because it's the paradigmatic example of a relativistic (gauge) field theory?

Also relativity is just a smooth continuation of the "good old classical physics". It's just "repairing" the inconsistencies of classical physics as far as the spacetime description is concerned, dealing with the intrinsic contradictions between the Galilei-Newtonian spacetime structure with Maxwell's electrodynamics. All of what you call "classical physics", based on Galilei-Newton spacetime, was very quickly "translated" into its relativistic version (though it took some decades to sort out some quibbles with subjects like thermodynamics).

In contradistinction to that quantum theory was really a revolution, which indeed forced the physicists to abandon the "old romantic" deterministic worldview, and that's why I would think that it's more appropriate to count relativity to classical physics while quantum theory is really something new.
 
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Delta2
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So is classical electrodynamics (Maxwell's and the Maxwellian's version of it) then classical, because it was definitely discovered in the 19th century or is not not classical, because it's the paradigmatic example of a relativistic (gauge) field theory?

Also relativity is just a smooth continuation of the "good old classical physics". It's just "repairing" the inconsistencies of classical physics as far as the spacetime description is concerned, dealing with the intrinsic contradictions between the Galilei-Newtonian spacetime structure with Maxwell's electrodynamics. All of what you call "classical physics", based on Galilei-Newton spacetime, was very quickly "translated" into its relativistic version (though it took some decades to sort out some quibbles with subjects like thermodynamics).

In contradistinction to that quantum theory was really a revolution, which indeed forced the physicists to abandon the "old romantic" deterministic worldview, and that's why I would think that it's more appropriate to count relativity to classical physics while quantum theory is really something new.
Classical Electrodynamics are part of classical physics, they were discovered in the 19th century and no one knew back then what is a relativistic gauge field theory and that CED is one such theory

The inconsistencies of classical physics were known by the late 19th century. Relativity fixed some of them and quantum physics fixed some other. If I had to choose between relativity and quantum physics as an extension of classical physics I would choose relativity of course.
 

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