The h Bar

John Rennie

06:00

@KaumudiHarikumar look on the bright side, anything is better than thermodynamics :-)

DanielSank

@DavidZ This is, incidentally, not a Physics.SE issue: it's the old "teach a man to fish" thing.

user228700

@JohnRennie :-) At this point, I guess.

David Z

@DanielSank Of course, we're not the first to face this issue, but it is a site issue whether we want to abide by that principle or not. I'm assuming (or at least hoping) most people do.

DanielSank

@DavidZ Right. Now let's look at this another way:

We could pick a homework problem, and generate two versions of that problem with different numbers.

Those are not, strictly speaking, "duplicates".

However, as we both know, they can be seen as "instances of the same class, just with different parameters."

David Z

Sure

DanielSank

06:04

That's a very easy thing for you and I to understand, but for some n00bs, it might not be.

However, let's think about potential answers to those questions.

Hopefully, we mostly all know that you should work a problem algebraically and put the numbers in at the end. Therefore, the answers to those questions actually are duplicates.

I'm considering the idea that the best way to explain why homework questions are bad, and what homework questions are, is that they are questions which invite the same answer to an infinite set of possible similar questions.

user228700

@JohnRennie: Popping back in to ask if u've heard about the theory that Dumbledore made a horcrux(Fawkes). If u haven't, I swear to God it will blow your mind:

DanielSank

Obviously that's too abstract to be useful message to newish users, but I think it might get at why we don't like homework questions.

We just don't want to write the same answer over and over.

user228700

Harry Potter Theory: Dumbledore's Horcrux

►

user228700

Do let me know what you think(If u feel inclined to watch)

John Rennie

@KaumudiHarikumar I hadn't heard that. It seems a bit unlikely that DD would kill anyone to make a Horcrux.

user228700

06:07

@JohnRennie There is some ambiguity about who killed his sister Ariana.

user228700

He never finds out if it was his wand that cast the curse.

John Rennie

J. K. Rowling says not ...

user228700

Yeah, I know, she denied it. But the facts add up so perfectly that you're left wondering HOW J.K R didn't come up with this herself!

DanielSank

@KaumudiHarikumar Meanwhile I'm trying to figure out who Supreme Leader Snoke is. Different generations I guess...

user228700

@DanielSank Yeah, I have no idea what u're talking about :P

DanielSank

06:10

@KaumudiHarikumar Star Wars

David Z

@DanielSank Well... I do believe your point is valid, but also I think it only applies to the very worst (in the sense of "least suitable for the site") of the homework questions, which are the ones that present a specific homework problem, with specific numbers, and ask how to solve that specific problem.

user228700

@DanielSank Riight. Haven't gotten around to reading/watching any of it yet. Will do.

user228700

@JohnRennie: You should seriously consider watching that video. I promise that you will be left feeling pure AWE.

DanielSank

@DavidZ Are there questions not fitting that description which are still off-topic and considered homwork-ish?

user228700

Halfway through the video, I started jumping up and down, not able to contain my excitement. It's a bummer that J.KR denied it and all, but seeing as you've read all the books, it really would be something to think about, what they say in the video.

David Z

06:13

@DanielSank Yes, there are other types of off-topic homework-like questions, e.g. those which present a homework problem (note that I'm making a distinction between the problem, which is the thing posed to the student, and the question, which is what they post here) and ask how to do problems of that class, in general.

user228700

If u do watch it, let me know what u think :-)

David Z

Or questions which present a homework problem and show some progress toward solving it in a general way, but just ask "what should I do next?" (At least, I personally believe those should be off topic)

DanielSank

@DavidZ I suspect that those questions are only considered off topic because the subject matter is too elementary to interest us.

John Rennie

I don't have the 17 minutes to spare, but I've found a text version here

user128101

@JohnRennie, Hi shall I repeat the question? btw, I read you might runfor mod, I strongly advise it. As to your fears about mod's VTC being binding, that's great! your judgements are extremely balanced and reliable, that would be a blessing so we don't have to wait hours before a question is put on holdand in-between gets answers.

DanielSank

06:14

We've already gone outside the bounds of what I wanted to discuss. It's clear I need to think about this more.

Thanks.

David Z

@DanielSank sure, no problem

user228700

@JohnRennie Cool! After u read it, let me know what u think :-) Toodles! (For now)

David Z

@DanielSank Personally, I don't want those questions answered because I don't want to reward a student who doesn't put in any effort.

DanielSank

@DavidZ I'm not entirely sure I like that reasoning.

Note the "entirely".

John Rennie

@user104372 We can start with a neutron and let it decay, and that's fine because a proton is lighter than a neutron.

Now we add the proton to a nucleus by some means and we let that nucleus beta+ decay.

David Z

06:16

@DanielSank if further thought would make you more sure one way or another, I guess that is something to think about

John Rennie

The mass of the nucleus will go down when it beta+ decays, but that decrease is due to increased binding energy of the nucleus.

DanielSank

@DavidZ The problem is that I can do much the same thing but with an "advanced" topic, and when reading such a post, we all feel ok because we don't think the answer is obvious. We don't mind the lack of obvious effort because we figure that in order to be able to pose (bad) questions on advanced topics, OP had to make a lot of effort at some point.

user128101

@JohnRennie, Yeah ,a p is 2.5 Em lighter than a n. If it beta-decays loses one positron +. That neutron is 3.5 Em+ lighter than any other n? right?

David Z

@DanielSank I dunno, I've seen bad questions of this nature about things like quantum field theory, which I would consider equally off topic. They're rare, for sure, but not unprecedented.

John Rennie

@user104372 No. The nucleus as a while has decreased in mass, but that doesn't mean the mass of any proton or neutron has changed.

The mass of a nucleus is not equal to the sum of the masses of the neutrons and protons inside it.

DanielSank

06:18

@DavidZ Perhaps.

John Rennie

This seems bizarre. The obvious question is how mass can just disappear. But it's true.

DanielSank

By the way, I want to reiterate one thing.

user128101

@JohnRennie, hasn't the individual p lost a positron?

John Rennie

@user104372 yes, but the energy to create that positron came from the increased binding energy of the nucleus as a whole, not from the proton.

DanielSank

@DavidZ I kinda think discussing the site's goals and trying to understand why people vote to close questions as "homework" is a bit of a waste of time. We know the homework policy is badly written. It's self contradictory and confusing. I think we could make a definite improvement by just fixing the wording a bit even if it's not perfect.

I already posted about this on meta. Just reminding you and whoever else might read this that that's what I think.

David Z

06:21

@DanielSank so... you're in favor of fixing it only a little bit, rather than dumping it and coming up with something new? I'm not sure I understand your point there.

user128101

@JohnRennie, to create a positron you need pair production, can you describe the mechanism that changes bindin energy to a positron?

DanielSank

@DavidZ I mean that we're trying to do the impossible and conduct a useful social science experiment, while we could just fix the obvious problems.

user128101

isn't the positron expelled from the nucleus?

David Z

@DanielSank What are the obvious problems, and how would we fix them?

John Rennie

@user104372 The creation of particles is described by quantum field theory.

Let me see if I can find a related question ...

DanielSank

06:23

26

Q: Should we rename the homework policy?

The homework policy is a constant source of confusion for new (and sometimes established) users. We see this confusion, for example, when users respond to closures based on the homework policy by defending their post with "This is not a homework problem", or similar. Some users have even been con...

user128101

@JohnRennie, is the positron ejected from the nucleus?

John Rennie

@user104372 yes, and the mass of the nucleus decreases as a result.

It's the mass of the whole nucleus that decreases, not the masses of the individual particles inside it.

DanielSank

I think there are one or two phrases in my proposed reworded that could be up for debate, but frankly I think the exact choice is a lot less important than getting rid of the existing allusions to "homework".

user116211

What to do with this?

user116211

0

Q: What is the optimal design for a top-loaded balsa wood bridge?

These are the specifications for the bridge I have to build, but I was wondering in general what tips I might be able to get for balsa wood bridge building.

homework-and-exercises building-physics

DanielSank

06:25

Just call it the "Request for calculations policy" and be done with it.

user116211

Definitely it's a homework.

John Rennie

@user104372 For some background have a look at:

44

A: What keeps mass from turning into energy?

This is inevitably going to be an unsatisfactory answer because your question is vastly more complicated than you (probably) realise. I'll attempt an answer in general terms, but you have to appreciate this is a pale shadow of the physics that describes this area. Anyhow, Einstein was the first ...

DanielSank

Yes, people will still use it to close questions which are not strictly "requests for calculation".

Yes, people will use it to close whatever they want to close.

David Z

@DanielSank Sure, but what I'm asking is: are you saying that keeping the existing policy mostly unchanged, and just removing references to homework (including in the name of the policy), is a better course of action than scrapping the policy entirely and making a new one?

DanielSank

But at least the people getting their posts closed will have a better idea of why.

@DavidZ No, but I think it could be done with an hour of work and would make the site better, whereas we've been going on about scrapping the whole thing for months and are now engaged in navel-gazing questions about the site's purpose in the Universe ;)

heather's post on meta about the goals of the site is, in my humble opinion, a massive red herring.

It asks about "who" the site is for, etc. rather than directing attention at how to encourage good questions.

David Z

06:28

@DanielSank I disagree. I think if we make that change, it will lead to one of two things: either a large number of questions which we currently close (IMO rightfully so) will no longer be closed, or those questions will be closed with a reason that does nothing to explain how they should be improved to make them on topic.

user128101

@JohnRennie, what I do not understand is this: you say the ejected ositron comes from the nucleus, yet there must be one p that becomes a n, and that can happen only if it gets an e or loses a positron, right? so what happened to the individual proton that is affected? if it is ejected from the atom, will it lose an electron?

DanielSank

@DavidZ Can you point to an example of such a post?

David Z

@DanielSank let me see what I can find

John Rennie

@user104372 suppose we take an atom in an excited state. When it relaxes it emits a photon. So we have a new particle being created, the photon, that escapes from the atom. However we don't say the electron has got lighter because it lost an electron.

David Z

0

Q: Help understanding term symbol

Term symbols are always used in spectroscopic data sheets, so I'd like to know exactly how to interpret them. I've come across the following sample problem: List the possible term symbols $\left(^{2S+1}L_J\right)$ describing the following two-electron atomic configurations: $$(1s~ 1s),~~~(1s~...

atomic-physics notation spectroscopy

John Rennie

06:31

In a nucleus the protons and neutrons are in orbitals like electrons in an atom.

But the situation is more complicated because protons can turn into neutrons and vice versa. In this case the nucleus with the proton is effectively in an excited state and it can decay into a lower energy state by changing the proton to a neutron and emitting the positron.

DanielSank

@DavidZ You closed that unilaterally?

user128101

@JohnRennie, that's because the photon has no mass, of course!Here we are ejecting mass in the form of a positron, wherever the energy comes from the proton itself has to be modified if it has to become a proton.So either it loses a positron and loses mass or it gets an electron and gain mass. No third option

John Rennie

In high energy physics mass and energy are the same thing and are related by the famous E = mc^2.

When an excited hydrogen atom emits a photon of energy E the mass of the hydrogen atom decreases by E/c^2.

David Z

@DanielSank yes, that's what the banner shows

John Rennie

There is basically no difference between emitting a photon and emitting a massive particle.

Either way the mass will decrease.

DanielSank

06:35

@DavidZ Well anyway, that would remain off-topic. I don't see the problem.

user128101

@JohnRennie, yes, but a neutron is a concrete object , tell me how a proton can become a neutron without changing its charge and mass

David Z

@DanielSank It's not a request for calculation. It wouldn't be covered by your proposed renaming.

Here's another:

0

Q: Newton's Laws: Child holding a wagon on an incline, with a handle also on an incline

I am having trouble with a question about a question, this is the original question. From my grade 12 physics class. Having hauled it to the top of a tilted driveway, a child is holding a wagon from rolling back down. The driveway is inclined at 20 degrees to the horizontal. If the wagon weig...

homework-and-exercises

and another:

-4

Q: Find the angle at which the body falls

Pls tell me if there is any conceptual mistake which i did. Thanks

homework-and-exercises work

John Rennie

@user104372 in quantum mechanics nothing is a concrete object. In a nucleus the identities of the protons and neutrons are not fixed. Protons and neutrons can be treated as different excited states of the same particle. See the Wikipedia article on isospin.

user128101

@JohnRennie, I got that, but take a Bdecayed neutron out of the atom, its charge is null because it lost a positron or not?

DanielSank

@DavidZ Calculation requests, e.g. "A 4kg ball is traveling at 8m/s in the x direction, how do I find...", or requests to have your work checked, e.g. "Here's my calculation, but the answer is wrong, where did I mess up?"

Physics - Stack Exchange is not a problem solving or review service. If you have a question about a specific problem, narrow it down to the specific concept that is giving you trouble and ask about that.

^ How's that?

John Rennie

06:40

I have to go away and do some work for a bit. I'll be back in about an hour and a half (8 a.m. UTC).

user128101

@JohnRennie, and when it loses an electron it is not in an excited state, where does the electron come from?

David Z

@DanielSank better, but there are still be some things it misses, e.g. homework questions which ask a conceptual question and show no prior research or work whatsoever.

DanielSank

@DavidZ I bet you a half dozen baozi that prior research effort isn't actually important to us. If it were, we'd close most of the questions on this site.

David Z

There's also the issue of non-homework questions which show no prior research at all. Those aren't covered by our current policy, nor would they be covered by your proposed revision, but they often get closed anyway. There is certainly some interest in disallowing those questions.

DanielSank

We only use prior effort as a criterion when it helps us close a question we don't like for other reasons.

@DavidZ They do not get closed, dude. Like, ever.

Almost all of my posts are in that boat.

David Z

06:44

@DanielSank Sure they do. Not all of them, but there are examples. Let me find some.

DanielSank

@DavidZ Yeah you can find some, but I would guess 30% to 50% of all the "good" questions on this site have no prior research effort.

I mean hell, our highest voted question of all time has no prior research effort. The answer, on the other hand...

exhibit A

exhibit B

exhibit C

David Z

OK, then how do you reconcile that with meta posts like this and this, which show strong support for not allowing questions which don't show sufficient prior research?

DanielSank

@DavidZ The first link just says "we should require research effort". That is absolutely not the same thing as evidence that users here actually enforce that requirement with anything resembling consistency.

David Z

See also this, this, and this

DanielSank

I note that both of the first two links were answered by @JohnRennie.

And I see no way in which the second link adds anything beyond the first.

David Z

06:52

@DanielSank I'm not claiming that it is. I'm only claiming that there is significant support shown on meta for closing questions for not having sufficient research.

@DanielSank They're examples of questions closed for not showing sufficient effort. I mean, if you'd be satisfied with one, I could have just posted one ;-)

DanielSank

@DavidZ The more we talk about this, the less I think votes on meta are a useful indicator of how folks actually use the site.

@DavidZ Second link in your first comment, not second set of links ;)

Haven't gotten to the second set of links yet.

David Z

ah

@DanielSank That may well be true. So, if we accept that premise, the issue becomes: (1) should our policies reflect what people say on meta, or how they actually vote (for closure)? (2) if the latter, how do people actually vote?

DanielSank

@DavidZ To put it rather bluntly (but clearly): I think a lot of the meta questions are horribly unclear and should be closed as unclear what you're asking.

We're looking at votes on posts that are so broad and vague that the votes just don't mean anything.

That, by the way, is why I think heather's post on meta is not good.

David Z

@DanielSank you can certainly cast your vote accordingly, but that doesn't address the issues I mentioned in my message.

DanielSank

If you actually read what she asked, it's a set of vaguely related, broad questions which actually contain implicit suggestions which I find horribly wrong.

@DavidZ Very well.

Should our policies reflect what people say in meta? Yes.

However, I think it's important to actually read the meta question so that we understand what people are voting on.

David Z

06:58

@DanielSank Then how do we get people to vote in a way that reflects what they say on meta?

DanielSank

If they're voting on "Do you like any of the following: strawberry, vanilla, chocolate?", then the votes mean nothing.

@DavidZ Back up. I'm saying that a crap meta post doesn't actually provide any information.

Also, I don't understand why you're suggesting that policies must reflect either 1) the meta, or 2) how people actually do vote, as if those things are mutually exclusive.

David Z

@DanielSank You said those two things were different.

DanielSank

@DavidZ I said that the meta posts are so unclear that I don't know what information they contain.

(in several cases, not all)

David Z

I mean, you put forth the idea that they are different, and I said let's proceed under that assumption.

7 mins ago, by DanielSank

@DavidZ The more we talk about this, the less I think votes on meta are a useful indicator of how folks actually use the site.

DanielSank

^ yes. "Not a useful indicator" is not the same thing as "contradictory".

A rubber duck is not a useful indicator of the electron mass.

David Z

07:01

So what do you mean by "not a useful indicator"?

DanielSank

I mean not a useful indicator... like... the instrument doesn't measure what I want.

...in some cases...

> If they're voting on "Do you like any of the following: strawberry, vanilla, chocolate?", then the votes mean nothing.

The answers are all "yes" and we've learned nil about people's ice cream preference.

David Z

Yeah, that's what I'm talking about. The instrument (a meta post) measures one thing, but what you want (actual voting patterns) is something else. So which one do we base our policy on?

DanielSank

@DavidZ Is "you" in that sentence rhetorical?

David Z

Yeah

DanielSank

@DavidZ I don't want to base policy off of voting patterns. I personally think a lot of the close votes use the wrong reasons, for example.

(I'm thinking about whether or not I mean what I just said)

(I think I do)

Let's use your three example posts to find out.

David Z

07:04

I'm not counting reasons as part of the voting pattern. For the purposes of determining our scope, voting pattern means, does the community consider the question on topic, or not?

DanielSank

@DavidZ oh

Well, of your three examples, one was just a duplicate.

David Z

@DanielSank Ah, I missed that. But you could imagine that the original didn't already exist on this site, and in that case I think it would still be a decent example of my point.

DanielSank

@DavidZ Not sure. "What is charge" is a pretty damned deep question.

If anything it's too broad.

Interestingly, too broad is probably often a result of a lack of effort.

David Z

OK, but then the question is, can most questions which do not show sufficient effort be closed as too broad?

DanielSank

@DavidZ No comment. I'm not sure.

About the helicopter question, I don't think that's a bad question at all.

It's low level, and the answer is obvious to me, but it's not really a bad question.

Or perhaps it is and this is where you'll get me to understand something new.

David Z

07:10

@DanielSank Yeah, me neither. If that is the case, it would be very relevant to our ongoing policy discussion.

DanielSank

@DavidZ, is this a bad question: How can redshift be used as a measure of distance, given that both relative motion and the expansion of spacetime lead to redshift?

@DavidZ Noted.

FWIW I always try to vote to close for reasons other than "off topic" when possible.

David Z

@DanielSank If that's all there is to it, here is why I consider it bad. Copy and paste the question into Google and the second search result is "Relating Redshift and Distance".

DanielSank

@DavidZ So wait a minute, you'd vote to close that?

David Z

Maybe. If it were personally up to me, and I didn't feel some obligation to use my close vote in accordance with existing policy, I absolutely would.

At a bare minimum, I would expect the body of the question to link to that page and ask a more specific question about its content, or at least explain why the content is insufficient to address what the poster really wants to know.

DanielSank

@DavidZ I think you're saying this because I happened to pick an example you know stuff about.

That Google hit looks like an obviously digestible piece of information to your eyes, and so you find the question I posed to be kind of stupid.

David Z

07:16

Not stupid, just lazy. (To put it bluntly)

DanielSank

However, your reasoning could be applied to almost every question on the site.

You can Google just about anything.

Is that fact really grounds to close questions as lazy? No, not even close.

David Z

Sure, but can you Google any question title and find an obvious answer within the top 5 results? That is the operative issue.

well, 5-ish

DanielSank

@DavidZ I simply don't think that reasoning is uniformly applied to all questions on the site, or even uniformly applied by a given individual user.

David Z

Perhaps. So what?

DanielSank

So it's not a good criterion. Nobody is actually using it and I doubt anyone thinks we should.

As I pointed out, almost all of my own questions could have been answered if I put in effort.

Nobody closed them because they're on advanced topics.

David Z

07:22

Could all of your own questions have been answered by copy-paste into the Google search box?

DanielSank

Probably, if I were willing to read the hits. But I'm not. I use this site so that I can get other people to spend time constructing clear answers for my sake.

David Z

I picked a semi-random example: it's not clearly answerable by the top search results (excluding the question itself).

DanielSank

Let's not pretend that we on this site are answering previously unanswered questions. In fact, in a sense it's policy that we avoid that.

Therefore, you can pretty much bet your britches that every single question on this site can be answered via Google + reading.

@DavidZ That's one of the few questions I've asked where I mostly agree with you.

user128101

@JohnRennie, "... in quantum mechanics nothing is a concrete object.." can you give me a link of QM where I can see how a positron can be lost without a concrete positron being lost?

DanielSank

However, note that even there I showed zero research effort, the existence of helpful links on Google notwithstanding.

David Z

07:28

To be clear: I am talking about specifically copying and pasting the question title into Google and looking at the first window of results for obvious answers. Not going through all the results. Not using specially crafted search terms. Not hunting through research papers for tangential sections in the middle.

Although I think we may be getting a bit off track with this.

DanielSank

@DavidZ Of course.

@DavidZ Perhaps.

David Z

Here's another one (which I looked up while typing that previous message) not obviously answerable by top search results, unless this paper would constitute an answer

but anyway, it probably doesn't really matter

DanielSank

I did say that I think 30% to 50%, not 100%, of the posts on the site could be answered with Google.

I based that estimate off of my own question list ;)

And yeah, before I posted that question, I saw that there were papers out there.

They look really complicated, and I hoped that posting here I'd get the attention of someone who could explain it clearly and simply. I was wrong, unfortunately.

David Z

I'd guess that if I were to go through all your questions and apply this procedure to them, I'd find few or none answerable that way.

DanielSank

Most of the papers I found on that topic used math I don't understand.

exhibit D

Anyway, I get your point.

You're saying there's a judgement to be made on whether or not a "small" amount of prior research could provide an answer. yes?

David Z

07:35

It's probably more useful to get back to the main point, which was about how people claim, in meta posts, to be opposed to insufficient effort questions, but (we are assuming) they don't use their close votes that way.

DanielSank

I thought your position is that folks do use their votes that way.

Looky here!

244

Q: A mirror flips left and right, but not up and down

Why is it that when you look in the mirror left and right directions appear flipped, but not the up and down?

visible-light reflection geometric-optics

David Z

I used to think so, but over the past year or two I've come around to the conclusion that they don't

DanielSank

You protected that post. Why didn't you close it?

@DavidZ ah

@DavidZ Then what were we just debating? Lol. I'm really confused now :D

David Z

@DanielSank because it was protected three years ago and the requirements for prior research weren't fleshed out at the time. If it were asked today (and the original weren't there), I would close it. I would certainly hope to see the poster edit in some evidence of research and get it reopened, but as is, I would close it.

With that particular question, since it's so old and popular, I'm being a bit lazy and waiting to see what we decide about the requirements for prior research before closing it or not.

@DanielSank Anyway, I believe we were debating whether our policy should be based on what people say in meta discussions, or on how they actually use their close votes.

With insufficient effort being an example of an issue where, it seems, people use (or don't use) their close votes in a way that does not match what they say on meta.

DanielSank

@DavidZ So you agree with me that people are inconsistent about voting to close questions lacking prior effort?

This is what I'm so confused about now.

I was saying folks are inconsistent. I thought you disagreed.

David Z

07:41

@DanielSank Yes, if you're saying that people don't use their close votes in a way that reflects the outcome of the meta discussions, I agree.

DanielSank

@DavidZ facepalm

Ok.

I must be running my brain at half speed today.

David Z

I might not have been clear, either... it often happens in these discussions.

I think the fact that we've had this confusion just between the two of us, extrapolated to the whole community, says something about why it's taking such a long time to replace the homework policy ;-)

DanielSank

Hahaha, yes, very well said.

Oh my goodness we're a fine bunch, eh?

David Z

lol

If you ask me, this is the PITA part of moderation - trying to extract consensus from a big group of people with varying opinions, using a medium that makes clear communication at least moderately difficult

(no pun intended, not that it was a very good one anyway)

DanielSank

@DavidZ "moderately" difficult?

David Z

07:48

:-P

DanielSank

Oh, brother. Fine bunch indeed.

John Rennie

@user104372 I'm back! I don't understand what you're asking. Initially the positron didn't exist, then it existed, then it annihilates with an electron and disappears again. So a positron, like any particle, can be created and destroyed again.

David Z

@DanielSank if that's all for now, I should probably get back to debugging some C++ code

DanielSank

@DavidZ May the null pointers be ever in your favor.

David Z

hehe, thanks

same to you, I guess...

DanielSank

07:52

By the way, I think the ball's still in your court. I don't see how my proposed rewording fails to reject questions that ought to be rejected.

Calculation requests, e.g. "A 4kg ball is traveling at 8m/s in the x direction, how do I find...", or requests to have your work checked, e.g. "Here's my calculation, but the answer is wrong, where did I mess up?"

Physics - Stack Exchange is not a problem solving or review service. If you have a question about a specific problem, narrow it down to the specific concept that is giving you trouble, show effort to address the issue yourself, and ask about that. If the question can be answered by a quick Google search, it's off topic.

This needs a bit of language-smithing, but I maintain my position that with an hour of tweaking this we could make a huge improvement over the present homework policy.

I'm not entirely sure how to further this line of reasoning on meta, since I already wrote a post saying essential just that.

user116211

@DanielSank Hmm, never mind, but isn't it synonymous to the present reason Homework-like questions should ask about a specific physics concept ....?

DanielSank

Anyway, looking forward to further discussions.

@MAFIA36790 Yes, but it removes that damned word "homework".

user116211

@DanielSank Ah!

DanielSank

@MAFIA36790 please have a look at this meta post.

user116211

@DanielSank sure.

user116211

07:57

Anyways, what is the criteria for a differential relation to be holonomic?

user116211

Lanczos explicitly discusses that.

user116211

The crux of the point is the relation must be exact.

user116211

But, hmm, I couldn't get some of his points he asserted.

David Z

@DanielSank Ah, see you changed it from before ;-)

DanielSank

@DavidZ Yes, and I'm going to keep refining it.

Because I really think it's not so far off.

user116211

07:59

Let the relation be $$\mathrm dq_3 = B_1~\mathrm dq_1 + B_2~\mathrm dq_2\,.$$

DanielSank

...and I think all this kerfuffle in the meta is completely off in the weeds.

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