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It can be difficult at times to find quality derivations for 'some' of the basic formula used in high school physics, so I thought what if I post and self answer the basic derivations. Does this sound like a good idea, and would the community be in support of me doing this? I think it is good because it will introduce more people to the site (e.g., imagine it popping up as first result when google searching a famous formula).

Examples:

There are many more.

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  • $\begingroup$ Google already leads to several good sites. $\endgroup$
    – Jon Custer
    Commented Apr 12, 2021 at 13:24
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    $\begingroup$ I think it's hard to find the right resources @JonCuster (This comes from a person who has only recently started sticking to books) $\endgroup$
    – Brian
    Commented Apr 12, 2021 at 13:25
  • $\begingroup$ If a search was restricted to Wikipedia, would the examples be found there (not a rhetorical question)? $\endgroup$
    – Peter Mortensen
    Commented Apr 12, 2021 at 18:23
  • $\begingroup$ Yes wiki always has good 'leads' but I think at times it's too high level for someone in HS. Some article in wiki are written for a 'mature' audience to understand (by mature I meant experience with studying) $\endgroup$
    – Brian
    Commented Apr 12, 2021 at 18:24
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    $\begingroup$ I'm having a hard time seeing the tetrode equation as HS physics. Several of the others are pretty 'meh' to me. $\endgroup$
    – Jon Custer
    Commented Apr 12, 2021 at 18:31
  • $\begingroup$ I just searched up "derivation of equation" in search and took the first few result, the only one I selected particularly was the lens question $\endgroup$
    – Brian
    Commented Apr 12, 2021 at 18:44
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    $\begingroup$ I don't think we should be trying to replace textbooks wholesale. A decent introductory physics textbook will derive all the basic results it uses. We could create literally thousands of Q/As that essentially copy-paste individual paragraphs of such books, but that seems pointless to me. $\endgroup$
    – knzhou
    Commented Apr 13, 2021 at 18:28
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    $\begingroup$ I mean, it is true that there are many bad books out there that don't derive anything, like IIT JEE prep resources that ask the students to unthinkingly memorize long lists of (occasionally incorrect) equations. But I don't think we should try to fix that system by posting thousands of completely standard, well-known derivations, when the real fix is just to look in any decent book. $\endgroup$
    – knzhou
    Commented Apr 13, 2021 at 18:29
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    $\begingroup$ I think a better goal would be to try to be more specialized -- focus on a few specific derivations that are highly in demand, but hard to find. I don't think the lens equation is a good example, because that is derived in any decent book. But the Sackur-Tetrode equation could work, because to my understanding, everybody in the Indian high school education system is forced to memorize it, but almost nobody is told the derivation, and crucially it's not in introductory books. $\endgroup$
    – knzhou
    Commented Apr 13, 2021 at 18:39
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    $\begingroup$ Relevant example: physics.stackexchange.com/questions/212614/… $\endgroup$
    – Emilio Pisanty
    Commented Apr 14, 2021 at 12:55

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Something being useful in general does not mean it belongs here. CPR training is a very good thing to provide, if you are qualified to. But I think we can all agree this is not something that we should be doing here.

Good-quality derivations of canonical HS problems is a good thing in general. But this does not automatically mean we should be doing it here.

If the question asks for a derivation, then it will most likely be closed as off-topic. If the question asks for a conceptual explanation of something, then it will most likely be on-topic. Two notes:

  • The criterion is the question itself, not its (potential) answers.
  • The rule does not change if the question is self-answered, although in practice people seem to be slightly more lenient in applying the rules for these. YMMV.

If you plan to post a question "please solve this free-body diagram for me" and answer it in detail, please don't. It will be closed, and you'd be wasting everybody's time, specially your own.

If you plan to post a question which asks about the physics behind general problems, and then answer it in detail, describing general principles, then by all means go ahead. But again, be careful in how you frame the question/answer. The homework policy does not allow problem-solving questions, so if you don't word it properly it will be closed.

FWIW, my personal opinion is that it will be quite tricky to find a good balance. Low-level physics are for the most part just problem solving. So I'm not sure how you plan to provide conceptual explanations that are neither too vague to be useful nor too advanced for the intended audience. But you do you.

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    $\begingroup$ The first example was a bit uncalled for because like that's really blowing up the idea to an extreme which I didn't even intend in original post. Secondly doesn't a derivation count as a conceptual explanation of an idea? $\endgroup$
    – Brian
    Commented Apr 12, 2021 at 17:34
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    $\begingroup$ +1: I would like to add emphasis on the part that it could indeed be a great thing to ask a question with the sole intention of self-answering as long as the question is good. In my early days of learning GR, I came across a bunch of such Q&As on basic but conceptually interesting topics in GR by John Rennie and they were quite helpful. $\endgroup$
    – user87745
    Commented Apr 12, 2021 at 20:06

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