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https://physics.stackexchange.com/questions/74425/power-loss-from-chain-and-sprocket-combinations-of-equal-ratios

I'm simply asking what the difference of power would be to make an atv with a 13t sprocket accelerate the same as one with a 11t sprocket.

What am I asking to be engineered?

If you can't or don't want to answer the question, that's fine. But don't say its about engineering for a means to delete it.

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    $\begingroup$ Have you read our policy on engineering questions? (We define what we mean by "engineering" there) Especially the "applies our understanding of nature to specific, real-world problems". The major issue here is that the question is too specific (which makes it not too useful to other visitors) and isn't directly asking about a physics concept per se. $\endgroup$ – Manishearth Aug 19 '13 at 4:36
  • $\begingroup$ @Manishearth So if change the 13t and 11t to x teeth and y teeth, then you'll be happy? $\endgroup$ – Randy Aug 19 '13 at 4:38
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The issue is you are not asking how or why something works, but rather for the final answer. The only question you ask is "Would you agree its easier to accelerate the chain on the smaller sprocket than the larger?" which is not a physics question. The rest of your post is either background information or a "check my calculation" section.

If you would like your question re-opened, I would suggest that you find ways to pose it in a way that is looking for an understanding of what the physical differences might be between the two systems. Even removing the bulk of the information might help, the question can be as simple as "Why does power decrease as cogs become smaller at a constant gear ratio?"

The numbers don't matter from the physics standpoint, nor does the application. But if you can phrase it as a "Why does this work the way it does" question, it might be on topic and would (hopefully) give you the understanding of the problem to solve for the numbers yourself.

Just my two cents.

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  • $\begingroup$ The problem is, I already know the why, I just don't know how to arrive at the solution because I don't know if I know everything. I'm not sure what question to ask because I don't know what I don't know. All I know to do is present the problem and some good soul may say "yes but you forgot to include ____". $\endgroup$ – Randy Aug 19 '13 at 5:23
  • $\begingroup$ @tpg2114 Well stated, although I would suggest one correction: 'if you can phrase it as a "Why does this work the way it does" question, it might be on topic'. Questions are judged on a case-by-case basis so we can't say with 100% certainty if a particular revision will make a question on topic without seeing it happen. $\endgroup$ – David Z Aug 19 '13 at 5:23
  • $\begingroup$ @Randy That's fair, and I'm sure there are places on the internet where posing a problem in that way would be perfectly appropriate. I don't know of any specific ones, but you could try looking for an engineering forum. This is not the site for that kind of question, though. $\endgroup$ – David Z Aug 19 '13 at 5:25
  • $\begingroup$ What if I said its a homework problem, would that make it ok? $\endgroup$ – Randy Aug 19 '13 at 5:26
  • $\begingroup$ @Randy Maybe I'm confused by your comment, but if you know the "why" with certainty, then you should know if you included it all or not. I think you know the trend but not all the processes that cause the trend. Unless I misunderstood the material you presented. So asking for the "why" should solicit answers that explain all the physical processes that matter. $\endgroup$ – tpg2114 Aug 19 '13 at 5:27
  • $\begingroup$ @DavidZ This is exceedingly frustrating. I see questions asking for specific answers and then see lots of answers in great detail. $\endgroup$ – Randy Aug 19 '13 at 5:27
  • $\begingroup$ @DavidZ Done, thanks for the suggestion. $\endgroup$ – tpg2114 Aug 19 '13 at 5:28
  • $\begingroup$ @tpg2114 oh, the bolding was just to indicate the word I changed, I didn't mean you should actually make it bold in your answer. ;-) (well you can if you want to...) $\endgroup$ – David Z Aug 19 '13 at 5:29
  • $\begingroup$ @tpg2114 So all I need to do is ask "Why does a sprocket with 13t require an engine with more power to accelerate at the same rate as an engine with a sprocket of 11t?" $\endgroup$ – Randy Aug 19 '13 at 5:29
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    $\begingroup$ @Randy I can't say with certainty, but that would be much closer to being on topic (in my mind, and I did flag the original as off-topic). More general is better, so I would recommend dropping the numbers and just say "smaller." But as DavidZ pointed out, there is no way of knowing if it will be on topic without seeing it. Just don't take offense with it being marked off-topic, it's "on hold" so it can be worked on/improved so it fits with our goals/policies and hopefully gets you the answers you need. $\endgroup$ – tpg2114 Aug 19 '13 at 5:31
  • $\begingroup$ @Randy that's better, although bear in mind you're addressing a group of people who may not know what sprockets are or what 13t and 11t mean. So you'd have to explain what is going on in different terms. (You can expect that people will know what gears are, FWIW) Also, whether it's a homework question or not makes no difference in this case. $\endgroup$ – David Z Aug 19 '13 at 5:31
  • $\begingroup$ @DavidZ The bold just makes it a reminder of my own limitations in deciding the fate of the universe... It never hurts to be reminded of that ;) $\endgroup$ – tpg2114 Aug 19 '13 at 5:32
  • $\begingroup$ @Randy P.S. it will actually help if you can ask the question in a way that avoids using specific numbers of teeth. So even better than what you posted in your last comment would be "Why does a gear with more teeth need more power to accelerate at the same rate?" (If you ask this, make sure that when you say "acceleration" you mean the same thing physicists do, i.e. the rate of change of velocity.) $\endgroup$ – David Z Aug 19 '13 at 5:34
  • $\begingroup$ @tpg2114 Ok, if I ask it as I suggested, the responses I anticipate will only tell me what I already know... that the inertial and frictional forces due to the chain will be more meaningful to the larger sprocket. Where can I go to have the process of converting these concepts into numbers explained to me? I'm sure the math site will suggest I try the physics board. There is simply no place for me to put my queston, therefore in lieu of a better site, this question shouldn't be off topic here. $\endgroup$ – Randy Aug 19 '13 at 5:37
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    $\begingroup$ @Randy Unfortunately just because no other option exists doesn't mean that this is the catch-all. If you look at the Engineering policy there are suggestions for other places that it might be on topic. You might actually find help on Robotics or Motor Vehicle (but I don't participate in either so I can't guarantee they can help you). If you get good answers from somebody giving the concepts, you can see if they will help you in chat to work out the numbers. $\endgroup$ – tpg2114 Aug 19 '13 at 5:40

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