What is the policy on asking homework questions on Physics Stack Exchange?

  • What kinds of questions are considered homework questions?
  • Are homework questions allowed?
  • What should I include in a homework question?
  • Why don't you provide a complete answer to homework questions?

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3 Answers 3



It's not enough to just show your work and ask where you went wrong. If you just need someone to check your work, you can always seek out a friend, classmate, or teacher. As a rule of thumb, a good conceptual question should be useful even to someone who isn't looking at the problem you happen to be working on

What kinds of questions are considered homework questions?

A "homework question" is any question whose value lies in helping you understand the method by which the question can be solved, rather than getting the answer itself. This includes not just questions from actual homework assignments, but also self-study problems, puzzles, etc.

On the other hand, questions that come up in the course of doing a homework problem, but are separate from the main point of the problem, might not be considered homework questions. There's a bit of a judgment call to be made, depending on the context of the problem. If you're not sure, it's probably safer to treat your question as a homework question and later find out that it isn't, than the other way around.

Can I ask a homework question here?

Yes, but there are a couple of things you need to make sure of first.

As a general rule, we do not discourage homework questions, as long as they are related to physics. But do keep in mind that Physics Stack Exchange is not primarily a homework help site; it's a place to get specific conceptual physics questions answered. The list in the following section will help you ask questions about your homework in a way that fits in with the site's philosophy.

Also, make sure you know whether your learning institution (middle school, high school, college, etc.) and your teacher or professor allow you to consult other people, or to post the exact question on the internet. This is usually addressed by your institution's honor code or rules and regulations, and any specific class policies. You should ask your teacher whether asking a homework question here is appropriate before posting your question.

How should I ask a homework question on this website?

  1. See if an existing question helps you

    Check and see if someone has already asked a question that gives you the information you need. The search box at the top right corner of the page will be pretty useful here, but you can also try looking at tags that are relevant to your question.

    If you find a prior question that seems relevant but doesn't clear up your confusion, mention it when you write your own question. That gives the people answering a better idea of what kinds of explanations don't work for you, and what might be more effective.

  2. Ask about the specific concept that gives you trouble

    We expect you to narrow down the problem to the particular concept that's giving you trouble and ask about that specifically. That produces a question that is more relevant to others who might be having the same problem, as well as probably more interesting to answer. As a side effect it shows that you're not just being lazy and trying to get us to do your work for you.

    The best way to produce a focused, specific question is to show your work. Explain what you've been able to figure out so far and how you did it. Showing your work will help us gauge where you are having problems: if it is a technical thing near the end, a short to the point answer will suffice; if it is some fundamental problem with understanding the subject, somebody will then write a longer, more detailed response. It will also prevent people from spending a lot of time going over ground that you have already covered or understand well already.

    It's not enough to just show your work and ask where you went wrong. If you just need someone to check your work, you can always seek out a friend, classmate, or teacher. As a rule of thumb, a good conceptual question should be useful even to someone who isn't looking at the problem you happen to be working on. Of course, it's still good to include the text of your problem, just in case (more on that a few paragraphs down).

    Don't just copy the exact problem from your homework assignment or textbook. In particular, when you are asking for help, writing in imperative mode ("Show that...", "Compute...", or "Prove or find a counterexample: ...") is at the very least impolite: you are, after all, trying to ask a question, not give an assignment. It also turns many people off.

  3. Reference the source

    If you're asking about a specific homework problem from a textbook, include the book and the problem number, so that someone trying to answer the question can go look it up themselves if they need to. If you're asking about a specific problem from a custom assignment prepared by the instructor, it helps if you quote the complete text of the problem in your post. Again, this shouldn't be the entire content of the post - you still need to ask about the specific issue that's confusing you, in addition to quoting the problem - but you never know when the person answering might need additional information from the original problem.

  4. Use the homework tag

    Use the tag on your question, in addition to any other tags that identify the kind of physics involved. This lets answerers know that you're looking for an answer which explains the underlying concepts.

    If you don't include the tag, someone will usually add it for you. If that happens, don't think that we're accusing you of lying about whether your question is from a homework assignment! The tag is used for any question in which the point is to learn the method you're using to solve it, rather than just to get the answer.

Why don't you provide a complete answer to homework questions?

This is pretty well covered by a discussion on the Math Stack Exchange site.

Providing an answer that doesn't help a student learn is not in the student's own best interest, and if a solution complete enough to be copied verbatim and handed in is given immediately, it will encourage more people to use the site as a free homework service. In the spirit of creating a lasting resource of mathematical knowledge, you may come back after a suitable amount of time and edit your response to include a more complete answer. Or even better, the student can post his own correct answer!

If someone posts an answer to a homework-type question that gives away a complete or near-complete solution, in most cases it will be temporarily deleted.


The rules for how to properly post homework questions can be a bit confusing, so here are some examples:


A good homework question states the problem clearly, shows an attempt to work through it, and identifies the specific issue that is giving the questioner trouble. These questions demonstrate that pretty well.


These homework questions don't show any effort put into solving the problem, and they are too specific to be of use to anybody except the person asking. That makes them inappropriate for this site.

Where else can I go?

If your question was closed as off-topic on this site, and you are unable to formulate it in the ways explained above, there are still other sites where you can ask for help. We keep a list on the thread My question was closed on Phys.SE. Can you recommend me another internet site where my question might be on-topic?.

Parts adapted from https://math.meta.stackexchange.com/questions/1803/how-to-ask-a-homework-question

  • 89
    $\begingroup$ I don't believe that providing complete solutions is detrimental to students, and in fact I believe the best way for students to learn the basics of physics is to look at as many complete solutions as possible. I believe this method is far superior than asking the student to attempt to solve the problem by themselves. When a student has seen many problems, I believe they will have no trouble in developing an intuition to solve far more physics problems, and will have much more refined thought process than the students who went off on tangents trying to solve problems using unconventional me $\endgroup$
    – Kenshin
    Commented Nov 14, 2013 at 1:54
  • 44
    $\begingroup$ Not everyone asking a physics question is a student -- for some, the physics problem is a stepping stone in order to get to another area that is back in their own domain and they simply need help to cross the hurdle. An additional disadvantage of not being a student is the inability to have access to peers, teachers, etc. Unfortunately given these rules it seems stackexchange cannot be of help either. $\endgroup$
    – keyvan
    Commented Mar 23, 2014 at 1:01
  • 8
    $\begingroup$ @keyvan that's true, but also note what it says on the site's About page: "...site for active researchers, academics and students of physics and astronomy." All these people have ready access to peers and educational resources that they can and should consult before coming here. People who are not active researchers, academics, or students are still allowed to participate, of course, but the site isn't designed for them, and we generally don't cater to their particular needs. $\endgroup$
    – David Z
    Commented Mar 23, 2014 at 1:26
  • 57
    $\begingroup$ '-1'. I do not agree with this point:"It's not enough to just show your work and ask where you went wrong. If you just need someone to check your work, you can always seek out a friend, classmate, or teacher." There may be some Physics enthusiasts who just do self study and they have no one to check their work. The definition of Phys.SE does not include "enthusiasts" so you may say, this is not a website for them. My downvote is just my opinion. $\endgroup$
    – user31782
    Commented May 7, 2014 at 17:03
  • 9
    $\begingroup$ "This includes not just questions from actual homework assignments, but also self-study problems, puzzles, etc." - This seems too vague, I think it needs elaboration--what distinguishes a "puzzle" from any other question? As it is, this gets used as an excuse to shut down questions that people judge too "basic" even if they are not homework--I don't see why this question would qualify as a self-study "puzzle" but any more technical question about physics principles wouldn't. $\endgroup$
    – Hypnosifl
    Commented Dec 1, 2014 at 17:50
  • 1
    $\begingroup$ @Hypnosifl the point of including that text is that we don't have to distinguish puzzles from non-puzzles. The homework policy applies to all questions whose value is educational, regardless of whether they actually come from homework assignments. $\endgroup$
    – David Z
    Commented Dec 1, 2014 at 18:20
  • 9
    $\begingroup$ @David Z - What would define a non-"educational" question? Aren't the vast majority of questions asked on the site because people want to learn something about a specific area of physics? If your view is that any question asked for the sake of curiosity/learning is "homework", is that your personal interpretation or is it part of official policy? And if the latter, could you point me to a Meta or policy page stating this? $\endgroup$
    – Hypnosifl
    Commented Dec 1, 2014 at 18:33
  • 2
    $\begingroup$ @Hypnosifl Ask me in Physics Chat and I can address those questions $\endgroup$
    – David Z
    Commented Dec 1, 2014 at 18:57
  • 8
    $\begingroup$ "site for active researchers, academics and students of physics and astronomy" Thanks for pointing this out, it will save me lots of trouble. I won't participate on this site anymore, because I'm not an active researcher, student or academic. (just self learn things) $\endgroup$
    – Calmarius
    Commented Oct 20, 2015 at 22:20
  • 5
    $\begingroup$ @Calmarius well, one can be a student while self-studying, but if you don't think the environment of this site suits you, then that is probably the right decision for you. $\endgroup$
    – David Z
    Commented Oct 21, 2015 at 3:10
  • 2
    $\begingroup$ @DavidZ It was often a problem, that when I asked a question about the modern physics topics, the answers are often so obfuscated that only someone who already have BSc, MSc in Physics and Mathematics can understand it. Now I know why: the site assumes the asker are an university student working on their PhD or a researcher working in a lab, and it all should clear for the asker. The site doesn't cater for those who are just curious and learn Physics only for fun... $\endgroup$
    – Calmarius
    Commented Oct 24, 2015 at 14:36
  • 19
    $\begingroup$ I don't agree with the answerer opinion I self study Physics and I have no one to check my work or provide me some hints. I will never find out a friend, classmate, or teacher in my neighborhood to answer such questions. $\endgroup$ Commented Jan 17, 2016 at 15:35
  • 2
    $\begingroup$ @Marine1 Theoretically, if you 1) ask for a specific concept (i.e. "how can I solve problems like...") and 2) show some effort toward the solution (i.e. you explain, what you tried, and why it doesn't work), then your question could be acceptable. Unfortunately, in the current practice, even these high-level questions are mostly closed. :-( $\endgroup$
    – peterh
    Commented Sep 8, 2016 at 19:02
  • 2
    $\begingroup$ If I could have asked my profs, had any friends, i would have not come here :/ Even when I dont demand for solutions, neither blind math, yet still my questions are still getting close, just because of one simple reason: I used the word "Problem", Moreover, the person closed the question in under one minute, surely my question still require reading time of more than a minute, which really makes me question just how thoughtful the question closing authority is while doing their task. $\endgroup$
    – Aditya
    Commented Jun 27, 2021 at 14:17
  • 2
    $\begingroup$ The term 'trivial' is relative, it seems that any moderator here has set their standard high enough to make any question of the entirety of undergrad it seems(perhaps even higher). Perhaps you will be contented to know that any question I ask, is that part that is not given in standard references, this place is already seems a very restrictive and demotivational, why would I care to come forth and ask here, hoping that I would get it right this time. $\endgroup$
    – Aditya
    Commented Jun 28, 2021 at 18:30


  • Your question looks like: "Here is my homework. Solve it instead of me, now".
  • You scanned/photographed your textbook.
  • You don't show effort or curiosity towards the solution.
  • You don't bother to begin sentences with capital cases or end them with a ".".


  • You aren't asking for the numerical solution; you want to understand how you can solve it for yourself
  • You are using Latex / MathJax formatting (tutorial here)
  • You explain: 1) what you want 2) what you tried 3) why it doesn't work

Don't forget: closing a question is mostly a subjective decision. The reviewers see a "close" and a "leave open" button next to your question. Although there are site rules, it is mainly up to them how to interpret these rules.

  • $\begingroup$ sorry, just to point out - you point out the bad point of not ending sentences with a ".", which I agree - but each of the 3 "Good" points you pointed out, does not end with a ".". $\endgroup$ Commented Jan 6, 2023 at 23:28
  • $\begingroup$ @WilliamMartens It is a pointed list. You are probably a native English speaker. Reading much more makes such trivial rules deeply imprinted in your brain. As I started pregrad education, one could not even start a physics education without had reading ten times more. So none of us had any problem to end sentences correctly, actually we have learned it at as about 6-7 years old children. $\endgroup$
    – peterh
    Commented Jan 8, 2023 at 10:35
  • $\begingroup$ it was more like a joke. And, while agree it is good, if the question is missing a few details here and there it doesn't make it really unreadable. But, I of course agree with you. Just wanted to point it out :) I mean the bad list has '.' while the good doesn't (it was this my reaction was based upon). Either way, wishes from Sweden! $\endgroup$ Commented Jan 8, 2023 at 11:18

The aim of our site is to be an authoritative source of information for active researchers, academics and students of physics and astronomy, and we want the posts here to be interesting, informative and reliable. To this end we sometimes close questions that don’t fit with the goals of the site. This answer explains why we sometimes close questions as homework and exercises, and how you can word your question to avoid it being closed.

There are two main things we consider when deciding whether to close a question.

The first criterion is fairly obvious: the physics community isn’t going to take us seriously if there’s any perception that we help people to cheat with their course work. So if you post a question that’s obviously been copied and pasted from a homework assignment we’re going to close it immediately. We can’t read your mind, so we can’t be sure whether your question really is homework or not, but we will err on the side of caution. If your question looks like homework we will close it. If your question isn’t homework then it’s down to you to explain that in your post, which brings us to the second criterion.

The second criterion is a little more subtle and is related to our aim to be interesting and informative. As a general rule homework problems and/or worked exercises are used to reinforce something you’ve been taught. For example if you do a special relativity course you will be taught about time dilation and how to calculate it using the Lorentz transformations. Then you’ll be given endless homework problems requiring you to do basically routine calculations like finding the lifetime of atmospheric muons or whether a fast moving pole will fit in a barn.

Our view is that while the routine calculations are important this site isn’t the place for them. The problem is that (a) they are routine and (b) there are a near infinite variety of such questions, and they would swamp the site. So if you post a question that is of this type we’ll probably close it with the tag [homework-and-exercises]. That doesn’t mean we think it’s a bad question, just that this site isn’t the place for it.

If you find yourself wanting help with a homework-like question then it’s probably possible to rephrase it into a more conceptual question. For example rather than asking about the lifetime of a muon traveling at $0.99$ you could reword your question to ask how we use the Lorentz transformations to calculate time dilations.

  • $\begingroup$ It is impossible to distinguish whether a student is "cheating" or is finding the answer for self-practice by only reading their questions posted online. $\endgroup$
    – IvanaGyro
    Commented Oct 16, 2022 at 5:58
  • 2
    $\begingroup$ Correct answers are necessary on the path of learning. We can fire a rocket because we don't ask students to figure out the relationship between mass and force when an apple falls down from a tree as Newton did. We can fire a rocket because we directly provide $F = ma$ to students. $\endgroup$
    – IvanaGyro
    Commented Oct 16, 2022 at 6:05

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