Timeline for Concept Definitions In Physics eg. $W=\int \vec{F}\cdot d\vec{x}$
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7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 28, 2019 at 7:33 | vote | accept | Luca Ion | ||
| Apr 27, 2019 at 12:27 | comment | added | BioPhysicist | @LucaIon You just need to read things carefully and think about what the equations presented to you really represent. | |
| Apr 27, 2019 at 12:25 | comment | added | BioPhysicist | @LucaIon You can tell from the context it is given in. Usually a book will use the word "defined", "given by", etc. Things with names are definitions, velocity, momentum, work, electric field, etc. Then you can derive relations between these from either math or experiments. Newton's laws, work-energy theorem, Gauss's law, Snell's law, etc. Or "derivations" could be something like "the momentum of a photon is given by $p=E/c$" where even though momentum is a definition you can derive what the momentum of something is in terms of other definitions depending on the system. | |
| Apr 27, 2019 at 10:44 | comment | added | Luca Ion | Allright I think I get it now thank you. But how do I know, when I get introduced to a new concept that the equations are definition and are not relations that can be derived from a more general definition? | |
| Apr 27, 2019 at 10:32 | comment | added | BioPhysicist | @LucaIon kind of, yes. Although these definitions probably had some motivation behind them than just making up random things out of thin air and seeing what works. The other answers go into some motivations behind the definitions. I really just wanted to point out that you don't derive definitions. You seemed to be hung up on this idea | |
| Apr 27, 2019 at 7:48 | comment | added | Luca Ion | Oh so you mean we defined some quantities like kinetic energy, potential energy etc. And then we also defined Work done to be a quantity that if it is non zero then that means it changes the energy of a system. And it just seems so that this arbitrary definition links very well with the other definitions we created thus it is useful? | |
| Apr 26, 2019 at 22:42 | history | answered | BioPhysicist | CC BY-SA 4.0 |