in this question I asked a specific concept and I have shown all my works and efforts behind it even though it was closed.

I just want to know where am I going wrong.

see this question

and more over i think that i am just asking a mathematical concept that which step would the particle hit.

so according to this post on meta.physics.stackexchange.com

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.

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    $\begingroup$ a mathematical concept is not asking for the answer. Here's a rule of thumb: ask yourself "Does my question involve or ask them to provide me with numbers?" If yes, then ask yourself "Is my question specifically about those numbers?" If yes, then it's a mathematical concept. If no, then it isn't. Asking us to tell you which step it would hit is not a concept, it is the answer. We would use math concepts to figure it out, but you are not asking us to explain those concepts. We know them, why should we test ourselves to solve your specific problem? $\endgroup$
    – Jim
    Jul 28, 2014 at 15:38
  • $\begingroup$ Try asking this, "What strategy should I use to approach this problem? If my straight line approximation doesn't work, how can I look at the problem and others like it so that I can imagine and formulate a solution on my own?" $\endgroup$
    – Jim
    Jul 28, 2014 at 15:40
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    $\begingroup$ If that doesn't get your question reopened, then we need to seriously take another look at our new homework policy $\endgroup$
    – Jim
    Jul 28, 2014 at 15:41
  • $\begingroup$ @Jim thanks for these comments i will surely edit my question now $\endgroup$ Jul 28, 2014 at 15:43
  • $\begingroup$ @Jim i have edited my post as you suggested $\endgroup$ Jul 28, 2014 at 15:59
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    $\begingroup$ @Jim To me the answer to that question would still just be "classical mechanics and specifically projectile motion". As such I'd still tend to call that "Too broad" so the question would remain closed, just for a different principal reason. I maintain that OP just needs to realize they're trying to play a computer game before properly knowing how to operate a mouse. There are quite a few videos on YT concerning projectile motion as well, if OP doesn't like or have access to books, though I'm slightly hesitant to recommend them because of the way they often teach this kind of subject. $\endgroup$
    – Wouter
    Jul 28, 2014 at 23:47
  • $\begingroup$ @Wouter That's fair. To be quite frank, I didn't fully read the question in question and based my recommendation and opinion on advice I consider generally applicable to all homework-like questions. $\endgroup$
    – Jim
    Jul 29, 2014 at 13:16

2 Answers 2


I'll pour the comment I made below my answer to your other question into an answer here.

Personally, I think despite the effort you've shown in the question at hand, the two main reasons for closing it were probably

  1. that you don't seem to have studied any classical mechanics and should probably do that first instead of asking here (for your own benefit). In a way, that's also what we mean by "effort". You should realize that to solve classical mechanics problems, one obviously needs to study a bit of classical mechanics first. It doesn't appear to me that you have done so. That's fine, but then you should understand that you might not (yet!!) have all the skills and insights needed. I don't know what books to recommend because I disliked the one book that I ever bought on classical physics but perhaps others can suggest a few.
  2. that the question doesn't really ask about a physical concept. You state you want the concept you're missing, but then I'm afraid the answer is simply "classical mechanics". Not that you would need the entire subject to solve those questions, but if you had studied some classical mechanics you would immediately know what type of question you were dealing with and how to go about solving it. I mean, I'm not saying this to discourage you, because we all started out not knowing it, but I really suggest getting a good book or other resource on classical mechanics.

I do feel this question is better than your other one that got closed recently in that it shows your effort. It's just that your effort displays a lack of knowledge about classical mechanics or even just particle trajectories, which would mean that an answer would be either a full course on this subject (which no-one will and should do, there are plenty of books and other resources) or very specific, only getting you to the solution of this particular question (which would mean you're likely to return soon with a similar question because you haven't understood the actual physics).

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    $\begingroup$ i am asking about the mathematical concept to come to a conclusion that which step would the ball hit $\endgroup$ Jul 28, 2014 at 13:34
  • 1
    $\begingroup$ I really don't see how your question is about a single concept, unless you view newtonian mechanics as a single concept. There is no concept there, what you need in order to solve the problem is an understanding of particle trajectories in classical mechanics. This really isn't a very tough subject and after you've studied it you'll quickly see both of your closed questions are in fact one and the same problem, except that there is an added difficulty of the stairs in this one. $\endgroup$
    – Wouter
    Jul 28, 2014 at 14:47
  • $\begingroup$ i want a mathematical concept to decide which step it should hit so should i post it on maths.se $\endgroup$ Jul 28, 2014 at 15:24
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    $\begingroup$ The Pick-up-a-textbook theme is echoed in this meta.SE answer. (Hat tip: Kyle.) $\endgroup$
    – Qmechanic Mod
    Jul 28, 2014 at 16:07

What's wrong with your post

When it comes to homework questions, there is a lot of discussion here on the Meta site. A more recent attempt to tackle the homework issue is a discussion titled Bite-sizing homework. Among the dozen answers in that post are the following two answers with votes in parenthesis:

Questions that can be summarized as "please check my work" are OFF topic. (+19/-7) link


Questions that can be summarized as "here a problem and my solution with my reasoning for each step, where has my reasoning gone wrong?" are ON topic. (+9/-7) link

I'd argue that your question follows the first of the two which seems to be decidedly off-topic (net score of +12). You could argue that it is the latter of the two, in which case it is split among voters (net score of +2), but if enough people with 3,000+ rep see it the latter way and think it is off-topic, it can be closed.

I do not actually see any specific physics concept in your question, you want to know if your answer is correct: does the ball hit the 5th step. This is, in my opinion, clearly following the first of the two above quotes.

More on Homework

Further, the homework policy states in point #2 under the heading How should I ask a homework question on this website? (emphasis mine),

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).

What you can do to fix it

In order to make the question on-topic, you might be able to tune it to the following spec (also taken from the afore-mentioned Bite-sizing homework post):

Questions that can be summarized as "Please explain what this aspect of a solution/derivation means or why it makes sense" are ON topic. (+23/-1) link

This will take some serious effort from you to make it decidedly on-topic. It may also be the case that you figure out your answer while trying to re-write the question. If that is the case, I still recommend completing the re-write so that your question can be re-opened & answered to be useful for future visitors with a similar struggle in the problem.

  • $\begingroup$ thanks a lot for this answer i surely follow your steps $\endgroup$ Jul 28, 2014 at 15:22
  • $\begingroup$ can i get my question reopened now $\endgroup$ Jul 28, 2014 at 16:00

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