How are equations derived from models in physics?

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The discussion centers on the challenge of understanding how equations in physics are derived from models, particularly in mechanics. Participants express frustration with the lack of satisfactory proofs in textbooks and seek recommendations for resources that provide theoretical evidence for these equations. It is noted that models describe real situations and cannot be proven but are validated through experimental comparison. Many equations in physics serve as definitions rather than derived proofs, complicating the understanding of their origins. Overall, the conversation emphasizes the importance of models in physics and the need for clearer explanations of how equations are formulated from these models.
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Hi I am currently studying physics (mostly mechanics)... however I find that books and teachers unsatisfying on the matter of proofs. I looked for books that give theoretical evidences but I failed to find any... does anyone have recommendations?
 
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What exactly do you want a proof of? Generally, I found Symon's mechanics to be quite satisfying proof-wise.
 
Not something exaclty, but on several things. I am looking for a book that prooves the equations that are given.
 
This depends greatly on what level you're looking at...
Algebra? Vector trig? Calculus? Diff.Eq?

IMHO, any instance where a theory is actually used
to describe a physical (real) situation (as an example)
that example is a "model" of reality.
You can't "prove" a model - you just try it,
then compare with the experiment.
If the model prediction is pretty close to the experiment,
you use that model again - if not, you toss it out.

If you're just starting, maybe most of the "equations"
are essentially definitions.
(Physics books tend to NOT distinguish equations with 3 lines).
Again, you can't prove a definition -
you keep useful ones and discard the non-useful ones.
 
lightgrav said:
This depends greatly on what level you're looking at...
Algebra? Vector trig? Calculus? Diff.Eq?

IMHO, any instance where a theory is actually used
to describe a physical (real) situation (as an example)
that example is a "model" of reality.
You can't "prove" a model - you just try it,
then compare with the experiment.
If the model prediction is pretty close to the experiment,
you use that model again - if not, you toss it out.

If you're just starting, maybe most of the "equations"
are essentially definitions.
(Physics books tend to NOT distinguish equations with 3 lines).
Again, you can't prove a definition -
you keep useful ones and discard the non-useful ones.

I could not say I am far into it, but I studied good part of mechanics, optics and accoustics. I understand that physics is built around models, but some equation are derived from the models, what I am looking for is how such equations are obtained.
 
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