I have come across several questions along the lines of "How do I complete this derivation?" where the answer sometimes is just mathematical, but generally they need some sort of physical insight to go from the original equation to the final one where the authors of the book/paper/etc pull the classic "And so it's obvious that..."

For a more recent example, Solving the Tolman–Oppenheimer–Volkoff (TOV) equation

while vertical wind gradients in the atmospheric boundary layer is actually an example that probably should be OT since it's purely a math question and no extra physical insight was needed... but I was feeling friendly.

So do we tag these as ? And more importantly, do we treat them as such and not provide the solution while also expecting the OP to include their work so far and where specifically he/she is stuck?


1 Answer 1


Actually, both these examples are suitable for migration to Math.SE. (I think so, anyway.) And in general, most questions where the OP is asking for help solving an equation should be migrated to Math, because the fact that they are asking about solving an equation means they've already done the physics which gets them to the equation. What's left is just math.

The only exception I can think of off the top of my head is if someone is specifically interested in a way to constrain or find the solution using physical arguments, like scaling behavior or dimensional analysis, not using normal mathematical methods. In those cases, the tag is usually not needed.

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    $\begingroup$ Nobody is interested in explaining how to solve such problems heavily related to physics at math SE. The to examples in the question would simply get no attention at all there, they would just be tumbleweeeds there. I know this from posting rather mathematical issues coming up when reading physics papers there. $\endgroup$
    – Dilaton
    Jul 4, 2013 at 8:04
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    $\begingroup$ @Dilaton that's neither here nor there when deciding what's on topic here. $\endgroup$ Jul 4, 2013 at 8:23
  • $\begingroup$ The other exception I can think of is when some approximation or assumption needs to be made and the justification is based on physical arguments. $\endgroup$
    – Kyle Oman
    Jul 17, 2013 at 13:44

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