I'd like to strongly suggest the Phys.SE community to carefully re-examine the following question and the reasons it was put on hold or regarded as not a good enough question:

Finding the period of an anharmonic oscillation by substituting the solution for SHM

OP's question about the potential energy being $|x|^3$ but it then described as simple harmonic motion seem completely legitimate to me.

The solution from the book doesn't satisfy the equation it is supposed to solve, as OP said there very clearly. What effort could OP be expected to make, for example explicitly trying and failing to solve the differential equation using the wrong solution? I don't think there is a reasonable effort lacking here, on the part of OP. As to the people voting to close the question and calling it homework, at the risk of being rude, I'm far from impressed about their level of effort.

It also clearly isn't a homework-like problem. OP asked whether that is a case of simple harmonic motion as the textbook says. The answer is that it isn't, and that the textbook he showed the image from is wrong.

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    $\begingroup$ To the extent that this goes beyond a homework question (and, moreover, one with very little effort put into it), it's as much of a closure through Unclear what you're asking. I see very little reason to reopen this one tbh. $\endgroup$ Oct 27, 2016 at 0:17
  • $\begingroup$ The solution from the book doesn't satisfy the equation it is supposed to solve, as OP said there very clearly. What effort could OP be expected to make, for example explicitly trying and failing to solve the differential equation using the wrong solution? I don't think there is a reasonable effort lacking here, on the part of OP. $\endgroup$ Oct 27, 2016 at 0:32
  • $\begingroup$ In its present form, I simply don't think it's up to scratch. If you think there's a quality question lurking there, then the thing to do is to edit it into shape instead of pushing for the current mess to be reopened. Keep in mind that this site is very different to math.se when it comes to homework(-like) questions. $\endgroup$ Oct 27, 2016 at 0:40
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    $\begingroup$ @EmilioPisanty - it isn't a homework-like problem, and there is nothing to edit. OP asked whether that is a case of simple harmonic motion as the textbook says. The answer is clearly that it isn't, and that the textbook he showed the image from is wrong. The people accusing this person of lack of effort deserve a prize in irony. $\endgroup$ Oct 27, 2016 at 0:44
  • $\begingroup$ The "powers that be", in this case, are those users with enough reputation to vote to reopen the question and so I suggest that you direct your appeal explicitly to that audience. But note that even if the question is reopened, it is quite likely that (1) the OP has moved on and (2) there is unlikely to be much interest in the question since most will simply note that the comments have already pointed out that the 'solution' (and its author) is very confused. However, there is one answer posted (currently deleted and so hidden to those without 10k rep) and so, if the question is reopened... $\endgroup$ Oct 27, 2016 at 0:57
  • $\begingroup$ @EmilioPisanty : Not up to scratch is not a closure reason. Suzu Hirose is right : how can she (or the OP) edit the question into shape when you have not identified what is wrong with it. It is perfectly clear what the OP is asking. What is unclear to you? ... It is not a great question, and perhaps not useful, but that is not a reason for closing either. $\endgroup$ Oct 27, 2016 at 3:25
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    $\begingroup$ The only thing that is unclear about the question is that the image is hard to read. I wish the OP had either retyped it (although if he did we wouldn't have believed that he copied it correctly) or gave us a better image. One could argue that this is a "check my work" problem (his work: he can make no sense of the question) but I think this is a special case. One does not normally see such a bad mistake in print, and a novice will need confirmation that the problem is just bad. $\endgroup$
    – garyp
    Oct 27, 2016 at 3:33
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    $\begingroup$ The question is now reopened. $\endgroup$ Oct 28, 2016 at 0:02

2 Answers 2


In its current form (v5), the question looks distractingly like a low-effort question about a photograph of a homework problem. It takes some effort, including squinting at the text in the photo, to determine that the asker is not having some trivial confusion about simple harmonic motion. As Emilio Pisanty points out in a comment, that makes the question fair game for closing as "unclear." We don't make a habit here of re-opening poor questions which were closed for the wrong reasons.

There are several interesting questions that could be asked about the $|x|^3$ potential as presented in that question, such as how the amplitude affects the frequency (already answered) and whether the textbook's solution is justified in approximating the motion as harmonic with some frequency (for which Fourier analysis suggests yes, it's justified).

If the question were edited to clarify which of those issues is of interest, the edits would probably place the question in the reopen review queue, where any user with 3k reputation can vote to reopen or to leave closed. In that case, re-opening the question becomes a community decision rather than a favor bestowed by the moderators.

  • $\begingroup$ distractingly? squinting at the text? These sound like excuses. Having confirmed that the OP is not having some trivial confusion about SHM, what justification is there for concluding this makes the question fair game for closing as "unclear"? The question seems perfectly clear to me. $\endgroup$ Oct 27, 2016 at 3:19
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    $\begingroup$ Just speaking generally, the fact that it is not clear makes a question fair game for closing as unclear. (Keep in mind that the fact that it's clear for you doesn't automatically make it clear to the community at large.) $\endgroup$
    – David Z
    Oct 27, 2016 at 5:54
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    $\begingroup$ @DavidZ : Are you saying the question is unclear? All 5 votes appear to have used the 'homework' reason. The 'unclear' reason was not suggested until Emilio Pisanty's comment. This sounds like bending over backwards to justify the decision made ("if it didn't qualify as 'homework' it would have qualified as something else") , rather than examine the issue objectively. $\endgroup$ Oct 27, 2016 at 16:00
  • $\begingroup$ As I implied by saying "just speaking generally", I am not saying anything about this particular question. $\endgroup$
    – David Z
    Oct 27, 2016 at 16:48
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    $\begingroup$ @DavidZ : Of course "unclear what you are asking" is a VTC reason. But that is not the issue. The issue is whether this particular question : is unclear. $\endgroup$ Oct 27, 2016 at 17:46
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    $\begingroup$ @sammygerbil Perhaps I can clarify. This particular question, in my opinion, is a marginally-okay question for several reasons, which I tried to explain above. Reasonable people might disagree, which is why there's a vote-to-close and vote-to-reopen process; however I now have only binding votes, so I'm staying out of the decision. I have some personal interest in editing the question to make it better and adding an answer, but I'm time-constrained for a few days. Perhaps the question will be re-opened by then. $\endgroup$
    – rob Mod
    Oct 27, 2016 at 19:55
  • $\begingroup$ @rob : Fair enough. I have edited already to make it clear that the OP was asking about your 2nd interesting question of whether the method used in the given solution is valid (even though it appears to be nonsense). Although the OP did not explicitly ask "is this method valid?", in rev5 he is clearly questioning the validity of that method of solution. (I guess your comment about squinting applied to the image before it was reorientated.) $\endgroup$ Oct 27, 2016 at 20:28
  • $\begingroup$ Indeed, "it takes some effort" to see why the question is a good one. That means the close voters weren't expending any effort at all -- not a behavior I'd like to see encouraged. If we close based on looks, we don't really have a policy at all. $\endgroup$
    – knzhou
    Oct 29, 2016 at 1:40
  • $\begingroup$ @knzhou that is the policy: close as many questions as possible. The real problem is the deficient SE site structure: tags, rep and voting are no substitute for subforums, a forum can have a range of topics, an SE site can't (try combining SE physics with SE parenting). The policy is focused on excluding questions and narrowing the scope, because it is the only tool available, there's no alternative to reduce "clutter". And splitting up is no option, because you need enough traffic to warrant a separate site. That's why Theoretical Physics SE failed and was merged with Physics SE. $\endgroup$
    – Previous
    Oct 30, 2016 at 18:36
  • $\begingroup$ @Previous I disagree that there is any "policy" of "close as many questions as possible," and I personally try to err on the side of leaving plausible questions open. My point here was (a) to observe that some questions are easier to understand than others, (b) in its original form, the question at issue here was particularly easy to misunderstand, (c) in such borderline cases, I trust the review queue. $\endgroup$
    – rob Mod
    Oct 30, 2016 at 19:27
  • $\begingroup$ @rob Well, it's my opinion that too many questions are closed (reason for me to quit the site), I merely suggested a possible reason other than elitism. But I was wrong, the volume can't be the problem when Stack Overflow can handle 50 times as much. $\endgroup$
    – Previous
    Oct 30, 2016 at 21:50

I agree. Not only the solution but also the answer is given, so it is difficult to understand the view that this is a "homework-like" question.

The OP has identified a conceptual issue with the solution provided in the image text. He is not asking "How do I solve this?" but "Is this solution incorrect or am I missing something?" Like you, I don't see what additional work could be attempted by the OP.

The question looks "homework-like." The problem is pasted in as an image; there is very little text from the OP and no calculation (v5). The homework tag was added by the 1st editor. Probably the decision to close was made because of what the question looks like rather than what it is.

I think it is easy for reviewers to follow the crowd and VTC because other reviewers (especially those with high rep) have already done so. On more than one occasion I have suggested (wrongly) that a question is a duplicate because of a superficial similarity, and other reviewers followed my lead swiftly and closed the question. For example : How does Newton's cradle with balls of different weight behaves?

I have edited the question and voted to reopen.

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    $\begingroup$ As David said, it's not enough that the question makes sense to you. If you think there's a worthwhile question there, put in the work to edit into a shape that's actually useful for future visitors. That's why we have the explainer badge series. $\endgroup$ Oct 27, 2016 at 12:46
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    $\begingroup$ @EmilioPisanty : How can I edit into shape if I do not know what you think is wrong with it? $\endgroup$ Oct 27, 2016 at 16:02

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