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1:56 AM
Q: Kinetic energy with respect to different reference frames

BartekI'm sorry if I shouldn't post here. I know almost nothing about physics so my questions can only be very basic. The faq says it's OK to ask questions at any level, but I've read something exactly opposite on meta. I'll just go for it because I have nothing to lose. I'm having problems understan...

That was flagged as a duplicate of this but I'm not so sure. Feedback from the community would be appreciated.
1 hour later…
3:19 AM
Q: What aspects of QFT do mathematicians find troublesome?

SWVWhat aspects of "conventional" quantum field theory (i.e. what's used by most practicing physicists) are considered to be lacking mathematical rigor?

NC I think?
1 hour later…
4:42 AM
@DavidZaslavsky I agree on NC
But I disagree on duplicates. The punchline is that 1 car at 100mph is different from 2 cars at 50mph not because of KE but because of the inelastic collision between two cars is different from the inelastic collision between a car and wall
Ie. two cars are more inelastic than car+wall system so the damage is different
That's more like it :-)
More like what?
agree with closing as NC
ah - I see it's been done
I helped out by flagging in case he wanted a record of it ;)
Some day I'll be able to vote to close...
4:52 AM
I will say though, as someone who partially qualifies as a mathematician, I find all of QFT troublesome
@tpg2114 thanks, that is very helpful
@tpg2114 I've hardly used that ability since getting it recently - David and CrazyBuddy are too fast for me
@DavidZaslavsky You're welcome, I'm glad to help out :)
@ChrisWhite ah, I should slow down a bit then ;-)
@ChrisWhite I'm a long way off... not enough questions I can answer to get there :p
4:54 AM
The long-term goal is, of course, to have the questions which should be closed be closed by community votes more often than by moderator intervention
all it takes is answering one that gets on the network-wide hot questions list :P
This is true
Unfortunately our questions rarely seem to make it there
@ChrisWhite If you ever want to be really troubled as a mathematician, look at the filtering operation in Large Eddy Simulation :/
@DavidZaslavsky Oddly enough, the ones that seem to make it are the ones I've flagged as OT at one point...
I could believe that correlation
Yeah, the popular questions tend to be the off topic ones and/or vice versa
There are a ton of old questions on Stack Overflow with upvotes in the hundreds that are now closed and deleted
4:57 AM
Should we bother answering [closed] questions? I mean... it's not what should be on the site, but voting seems to still work on them
And often they are easy to answer
Sorry... I got disconnected for a while...
Q: Relation between flow and pressure

M Murdochif you have water flowing through a 6 or 4 inch pipe what would the pressure be if tapped off through a 1/2 inch BSP tap. What would the equation be to find out the pressure at different flows?

Like that one I just got rep for recently (although I answered it before it was closed)
@ChrisWhite Woah.. Woah... See what happens when someone leaves the room for a while...
I'm not that fast...
The problem is - I'm totally spending my 5 days vacation (mostly here)
@ChrisWhite I think some questions recently got into "hot"...
like the BH sound, color perception (yours) :P
@CrazyBuddy Which brings me back to the point that off-topic questions are the ones that make the hot list :)
5:07 AM
lol - my greatest contribution to this site will forever be that one day I caused scores of people to try to see imaginary colors
@ChrisWhite :P
@DavidZaslavsky So are you looking forward to the next firefight and drama? I feel it brewing ;)
@tpg2114 uh... huh?
@tpg2114 Theoretically no, you shouldn't answer if you expect a question to get closed
@DavidZaslavsky Things like:
A: Please review our posts on the LHC

Ron MaimonThe difference between constructive contributions to a website and destructive contributions is very simple: constructive contributions add text with information destructive contributions remove text with information. Sklivvz sole purpose is to delete text, probably because it is easier to de...

@tpg2114 I was wondering how Ron responded :-)
He did a revision to a post today (which also seems to be a surprise)
5:13 AM
@DavidZaslavsky And the constant comments about attacking TP by somebody leveled against somebody else... Which I find irritating more than anything else.
Why these TP questions migrated here?
ahh the flamewars - makes me feel like I'm back on my undergrad mailing lists
It has cased so much of trouble all over our site...
@tpg2114 we have flags for that sort of thing, you know
We used to have a newsgroup, flame.news.gatech.edu
@DavidZaslavsky I've flagged a lot of things. You should know that by now :) I had mixed opinions on that answer, especially because the "question" didn't really pose anything to be "answered"
So I downvoted which felt more appropriate than fanning the flames
5:15 AM
Flagging is never fanning the flames
I don't know who can see flags honestly
I know some moderation tools kick in at 10k rep
If you flag for mod attention
@DavidZaslavsky Woah.. Not even the 10k (or 20k) rep. guys (access to mod. tools?)
@tpg2114 of the 8 houses at my undergrad, mine was the one most likely to have a meaningless flamewar on its email list, so all the others added digests of our list to theirs for the entertainment ;)
@DavidZaslavsky so what exactly are the mod tools?
5:19 AM
the faq just says "Vote to delete closed questions, access to moderation tools" at 10K
@CrazyBuddy Nope. It lets you see flags for closure, and maybe spam/offensive, but not other kinds I think
@ChrisWhite The mother meta deals with all these kinda questions...
Q: FAQ for Stack Exchange sites

Justin StandardCommunity FAQ For sites in the Stack Exchange 2.0 network To see a list of commonly used words and phrases, see the glossary. Asking questions How do I write a good title? How can I get answers fast? Is there a limit on how many questions I can ask? How should we deal with Google questi...

@DavidZaslavsky I actually worry that I flag too often, but maybe not since out of 52 flags here only 1 has been declined...
Well, I robbed that from Manish - during a chat
@DavidZaslavsky I think you've got some work on electric bills...
Q: Is electricity spent when we leave a switch on?

Mistu4uWell my question is pretty straight like the title. Is electricity spent when we leave a switch on? Or suppose a fan is plugged in but the fan is not switched on i.e. it is not using electricity, does it increase our electric bill then?

And I think I'm like 108/111 on SO... I have more time to police posts than answering them :(
5:25 AM
@tpg2114 don't use the decline rate as a measure of whether you flag too often. It only tells you whether you're flagging the right things.
You could probably flag about five times as many posts as you do without it being too often. (Not that I'm telling you to go start flagging things indiscriminately, of course :-P)
Unfortunately on a site like this, it's easier for me to recognize bad things than it is for me to answer good ones...
Mods, why is this question closed? physics.stackexchange.com/questions/51242/is-electricity-spent-when-we-leave-a-switch-on
@Mistu4u because it's off topic for this site, like the description says
Q: Is electricity spent when we leave a switch on?

Mistu4uWell my question is pretty straight like the title. Is electricity spent when we leave a switch on? Or suppose a fan is plugged in but the fan is not switched on i.e. it is not using electricity, does it increase our electric bill then?

@Mistu4u Umm.. Sorry for that. But, It is not necessarily Physics and doesn't require Physics to explain it.
It deals with economy or something similar...
5:28 AM
Well, electrical engineering really
But I know there is some physics formula which determines electric bills and it depends on the power we use. So my question rather states "Is power spent when we leave the switch on?"
And could actually go on something like skeptics if you rephrased it
You guys emphasized on bills a bit much!
@tpg2114 Yeah... Some reference links to the question would fit for Skeptics...
@Mistu4u there really isn't some magic physics formula to determine electric usage
5:30 AM
@Mistu4u Not really -- the "physics" formula is power used * cost per unit of power. Beyond that, it doesn't really apply to physics
we have some formulas relating to electricity, but in the real world there are just too many variables
@Mistu4u It's not a physics formula
What tpg2114 said
@Mistu4u These questions - are definitely on-topic in chat...
@Mistu4u check out this page: en.wikipedia.org/wiki/Standby_power
5:31 AM
@Mistu4u Even if you got more specific, like "Why does my TV use power when turned off?" that's not so much physics but an engineering/design choice
@Mistu4u You could ask these in h-bar anytime (if you have a doubt if it could be off-topic)
Which is to say -- you consume power when things are "turned off" because they ready themselves to be turned on quickly
the short answer is, you'll probably use less, but many devices still use some current when plugged in, even when not "on" - electrical engineers could tell you more
But if you had a light switch flipped to off so no power was going to the outlet, then no, it doesn't consume power
Thank you guys very much......I think I have got good references and explanations to study on.
5:33 AM
@Mistu4u As you can see now, tpg and Chris have already started the discussion :-)
:) :)
By the way, everyone remember we have a chat session tomorrow!
Well, today
in about 10.5 hours
@Mistu4u I think another term is "vampire power"
I have a presentation to give so I'll miss this one :(
5:33 AM
@ChrisWhite Busy... eh? - Presentation (meaning..?)
@tpg2114 that's the only term I've actually heard before - the wiki article is a redirect
I'll probably lurk but it's been way over my head the past few times
@ChrisWhite Me too actually, and when I searched for it, it pointed to that wiki article... Go figure :)
@tpg2114 we also discuss site stuff which is of general interest
@DavidZaslavsky Yeah, that's why I lurk. In case something I can actually contribute towards comes up
@CrazyBuddy yeah, six different people want things from me this week
5:36 AM
sometimes it's unfortunate to work for multiple profs
@ChrisWhite Ummm.. - Do u give some lectures stuff?
@ChrisWhite I think that may be better than 1 person wanting 6 different things at the same time... that's my usual situation
@tpg2114 agreed - at least I can say I'm busy with someone else :P
@ChrisWhite My advisor is a slave driver... I'm funded under one project, but I'm working on 3 others and my thesis is yet another :)
@CrazyBuddy I help give lectures, but that's easy compared to all the projects I've loaded up on
5:38 AM
@ChrisWhite Maybe, I should reduce my voice (being surrounded by Professors) :P
I've got a doubt guys...
@tpg2114 That's unfortunate
Maybe, I shouldn't have mentioned my age... Does age matter here?
and your work sounds hard to me
I'm curious... I've heard people from India frequently say "I have a doubt" when they would like to ask a question. But I've never heard that from any other nationality
@ChrisWhite Let's just say I wouldn't recommend what I do or who I work for to anybody... :)
@tpg2114 CULTURE of the soil maybe :-)
5:41 AM
@CrazyBuddy wow you make me feel old
@CrazyBuddy It's just an interesting phrase. I've never heard any other Commonwealth English speakers say that...
@ChrisWhite You and me both...
@ChrisWhite Ehm... Thats why I think of it...
I've spent 1/3 of my life in college...
If age is kept private, users won't know who this guy is..?
@tpg2114 Well, that's encouraging :P
If they see someone younger than 'em, there are probabilities for them to get rage...
How dare this idiot argue me? - stuff like that...
@CrazyBuddy For age, I don't think it matters if you tell people or not. Not to sound cynical, but it's usually easy to tell "younger" vs "older" than your current age. And it doesn't really influence opinions.
5:45 AM
@CrazyBuddy to be honest, you come off as young and excited anyway
@ChrisWhite Exactly my point :)
Look, the fact is if you are polite and interested in learning (ask good questions, leave good comments), then age doesn't matter. People will want to engage you and talk and teach because this is what we love to do. If we didn't, we wouldn't be on SE.
There have been 3 or 4 year old kids that I've been more interested in explaining physics to than college students because they were curious and interested
@tpg2114 Me too... Because, they'd be so basic that we've to explain from the start...
That Newton didn't really got hit by an apple :-D
More especially, they won't sleep when we teach 'em...
5:49 AM
btw, @CrazyBuddy, if you're 17, that gives you only 3 years to complete your PhD if you want to match someone I know :p:p
Even forgetting that -- when you teach somebody who is really interested; really curious... You can see that spark in their eyes. It's that little bit of fascination that we all feel when we learn something new
@ChrisWhite Hmm... For now, I must think of getting my BE - then whatever..!
an astro guy or some sort of...
It's a really pure, unadulterated interest in how and why things work. That's irreplaceable. It's not about a grade, it's not about a silly test. It's interest because something is fascinating
Wait a min... I just forgot what I came to say...
@tpg2114 Yes indeed... But, what about other things like VTC, downvoting, etc...
Some months ago, I explain the users why I downvote...
I think that may be a cause....
A guy named zephyr downvotes my posts everytime...
He's not around now...
Once he removed himself, I got +46 (seeing that I've got 23 downs..)
Now, I've stopped commenting for my downvotes unless the user seems to learn something from my comment (and mainly revise his post)
Guys have gone...?
@CrazyBuddy don't change the face you show the world just to please some close-minded people
5:55 AM
Still here... actually responding to emails from my advisor even though it's 1am...
Just another day.
@ChrisWhite I don't... I think I saw a post of Manish...
@Manishearth Hey Manish, you explained that downs and ups are meant to be private isn't it?
I guess I have it better - I'm just responding to emails from students concerned about their grades
@CrazyBuddy yep. though you can publicize your votes if you want. It's up to you
@ChrisWhite Already? Isn't the semester only like... a week old?
5:57 AM
we're still finishing up the fall semester
@ChrisWhite ah
some strange schedule with a monthlong "reading period" before finals
@Manishearth LOL
@Manishearth Well, from seeing that post - I comment only when the users seem to revise the post or argue with me (atleast)
@ChrisWhite I do enjoy the fact that in the south, we start our semester at the beginning of August -> first week of Dec. And start again first week of Jan -> first week of May
5:58 AM
@tpg2114 Eh..?
@ChrisWhite well technically "reading period" is only a week and a half. Although then there was that ~2-week Christmas break.
I don't know why I posted that.
Same here... (just about some 2 weeks ago, I completed my first sem)
@DavidZaslavsky Ours is only a week... but then 4 weeks for Christmas break :)
that can be nice - but trimesters are even better if you can find them @tpg2114 - spring break is after finals, so there's no worries
@ChrisWhite actually, a few of my profs have threatened to fail students early on (not me though ^.^) in the sem. Also, we have this policy that if you miss any lectures in the first week without any valid medical reason, you get deregistered.
6:00 AM
Unless you're a grad student... I got Christmas and New Years day "off"
@Manishearth Thats what all pro's do...
I actually got emails from my advisors for slides at 11pm on both days
@tpg2114 nice :-) Now I only have 2 weeks of Christmas break, except that it's not really a break
@tpg2114 that
And I had to meet him on Christmas Eve
@Manishearth Even in my colg., all pro guys are fond of engaging freshmen :-)
6:00 AM
...actually, I'm pretty sure I was working on Christmas day
@DavidZaslavsky ha! I got a month!
Sadly, I got only 4 days :-(
I know I was... Our days "off" just mean that he doesn't send us an email that day. But he'll send us one the next day asking for 2 days of work instead of one ;)
@DavidZaslavsky aha! you show your true colors (those being orange)
@ChrisWhite and black ;-) but not like I was ever hiding them...
6:02 AM
@DavidZaslavsky I almost went to PSU for nuclear engineering as an undergrad, and applied there for aerospace as a grad
@tpg2114 grad student?
@Manishearth Working on a PhD in aerospace engineering
@tpg2114 ah right.. Nice :)
@Manishearth Thats what I've already told... Maybe, I should keep "shushing" myself in front of the Phd. fellas :P
Actually, that means that you probably can answer @CrazyBuddy's software question
6:04 AM
@Manishearth Fortunately I do more fundamental research than engineering. I never liked "engineering." The whole "Get close then add 10% for safety" bugged me.
Which one?
yesterday, by Crazy Buddy
I (along with 2 other people) was thinking about designing some automated quadrotor- like aircraft
yesterday, by Crazy Buddy
So, Are there any simulation supportive software which allow to design more or less, an aircraft - taking dimensions, and other parameters as input, etc..., etc...
Ah. For a quadrotor, not so much
There's no "simple" software for that
well, I'm off to bed - good chatting
good night east coast; good morning India
@ChrisWhite Bye Chris... C'ya later :-)
6:06 AM
@ChrisWhite good night
Other aircraft that don't do crazy things, there's some software out there but mostly it's just a bunch of books with curve-fits in them that you plug into an Excel spreadsheet
@ChrisWhite 'night :)
@ChrisWhite Actually, I must get ready for lunch in about an hour...
Gd n8 Chris :-)
@tpg2114 I suspect that its much more difficult than I thought...
My senior design project -- we were given the specs for the Airbus A400M but weren't told what it was for. We made a spreadsheet in Excel in a week to design it last minute and got with 5% of the actual A400M design...
That's when I realized I didn't want to work in aircraft design
@tpg2114 Airbus..? Woah...
6:08 AM
Our professor was the project lead on the C130J so it must have been hard for him to give us the specs for the Airbus
Sadly, I'm very new to modelling... Just now entered - CAD
CAD is the first step... then you plug it into some sort of solid and/or fluid solver :)
@CrazyBuddy AutoCAD? SolidWorks?
@Manishearth Both...
But first you have to make a mesh around it
6:10 AM
@CrazyBuddy ah
@Manishearth Well, It started in my second sem.. BTW, It's quite interesting though
Not like first sem, I didn't like the syllabus at all...
@CrazyBuddy If you want to get into computational simulations in aerospace, at least in the US, you pretty much need a PhD. With a college degree, you can't get into it. With a masters degree, you basically just make the grids for the problems and with a PhD is when you can actually set up and run the simulations, plus analyze the results
Ah. I did it separately since in my robotics group I sometimes have to (a) model my designs and/or (b) 3D print them
@tpg2114 Actually, I don't think I'd spend my life in computers...
I just thought of doing something different...
Well, thats highly too much for my 4th year project...
At this point, my job is actually almost entirely software design
I haven't really done much "research"
Just a lot of code writing... for 4 years
6:15 AM
@Manishearth Maybe you're right totally. I should get help from some good seniors :-(
@tpg2114 Brainy..! :P
@CrazyBuddy Or stupid depending on how you look at it :)
@tpg2114 Any software available for beginners...?
There should be something good for students?
Regarding aircrafts...
Or atleast, you could point some known references (or books), so that I may dig into
to get some intuitive understanding :-D
@CrazyBuddy Aircraft or rotorcraft? There's a big difference between them unfortunately
And there's also a difference in design of the entire system vs design of wings (aerodynamics)
@tpg2114 Oops.. For now, Rotorcraft...
@Manishearth Now, thats for 8th grade buddies :-)
6:22 AM
@CrazyBuddy Unfortunately, I don't know much about rotorcraft... I've avoided that subject like the plague
@tpg2114 You've already started scaring me off :P
@CrazyBuddy To each their own man :) Georgia Tech is one of the leading universities for rotorcraft, but it's not what I'm interested in
A lot of people would be scared off by what I do
@tpg2114 Hah :-D
If you want to get started in numerical methods for airfoils (which also applies to rotors/propellers), check out XFOIL
So you've been writing an answer in the midst of chatting.? :-D
6:25 AM
Multi-tasking, it's the only way to survive grad school ;)
@tpg2114 Nice advice :-D
XFOIL is a fun code, it has it's limitations (which understanding how it works and what it's limitations are is basically the core of undergraduate aerodynamics -- potential flow)
@tpg2114 Well Ok tpg... Nice chat today...
But you can play with fun things
Gotta go for my breakfast...
at 1200 atleast :-D
@tpg2114 I'll ask you if I require something regarding the design..! :-)
@tpg2114 BTW, I'll check into that too..
6:28 AM
@CrazyBuddy If you have any aerospace questions, don't hesitate to ask
I'll be more than happy to help you understand the concepts
@tpg2114 Surely... (I think I don't wanna say "Cross my heart, Hope to die") :P
I'm gonna deal with the subject (for atleast 4 years)
C'ya later then :-)
Have a good night (morning)
actually, afternoon :P
Q: Are new elements still being created?

chubbycantorsetLast I heard, there were 115 elements (natural and artificial, of course). Are there more still being made? If so, why? I thought this question would be more appropriate on the physics site rather than the chemistry site. But if I'm wrong, do let me know, so I can post it there instead.

Should this be OK here or ought it be migrated off?
I answered it... I could use more rep on Chemistry :)
But I'd prefer rep here!
6:31 AM
@CrazyBuddy I know you flagged it, but I can't mention who flagged what in public :)
@Manishearth Well, Sorry...
@CrazyBuddy oh, no prob
@Manishearth BTW, I think the double mod does know the Chem FAQ already...
I gave away all my rep in a bounty on Chem and it turned out to be answered by a guy who works downstairs from me. I should have asked around in person first and saved my rep...
@CrazyBuddy I do. I wrote it.
6:33 AM
@Manishearth I thought of that...
But when dealing with overlap questions (which fit both FAQs), it's a completely different issue
My general policy is (for overlap qs):
Maybe we could wait...
If will obviously get much better answers elsewhere, migrate
Oh My, David's gone...
If it doesn't get answers in a while, migrate
6:34 AM
@CrazyBuddy only for a moment
otherwise leave
@Manishearth I think since there's nice physics answers possible due to potential discoveries about the nature of the forces involved in binding matter together, it may be better on physics
@DavidZaslavsky Oops.. Then, I'm right that mods are spying everything :P
@Manishearth I think it's okay here as it is really about nuclear science. When you create a new element, you make the nucleus, and the electrons take care of themselves.
@tpg2114 Interesting. About the "islands of stability" and all?
@DavidZaslavsky Like I said, it fits both FAQs :)
I'll comment for now. No need to migrate then
6:36 AM
Well, all that matters is whether it is on topic where it is.
@Manishearth Honestly I don't know -- but the quote I put in my answer, the scientist seems to say that it's possible to provide "more knowledge about the forces that bind nuclei and what causes them to split apart"
which it is IMO. I say don't migrate.
@DavidZaslavsky true, though it had a flag asking for migration
Which to me is more physics than chemistry. But it's well outside of my expertise (but not outside of my Google'ing expertise)
@tpg2114 ah. All those crazy models for nuclear stability, then (odd-even rule, nuclear subshells, etc)
6:37 AM
Well, Okay - Bye David, Manish, tpg (Hmm.. I've already told ya)
I'm off...
@Manishearth I know, but I don't think that's really a valid reason to flag.
For better or for worse, a lot of times I can answer questions I don't know anything about by searching the internet for a few minutes first...
I mean, flagging to say "if it's off topic it should go to X" is fine, but flagging to migrate when it's not off topic, not so much.
I don't know if that means I'm really good at searching for things or people don't put any effort into searching before asking
@DavidZaslavsky hmm, yeah
6:38 AM
@tpg2114 definitely the latter, perhaps also the former
@CrazyBuddy bye
That's my inclination also
It really bugs me when I can type in the nouns from the question title and get the answer in the first link
@DavidZaslavsky btw it is appropriate to migrate an "overlap" post if (a) the OP asks for it, or (b) it is obvious that it will get much better/focused answers on the other sites
@tpg2114 yeah...
There really should be a flag for "Answer in first link on Google"
@Manishearth I'm iffy about such things. If the migration is valid, it indicates that the topic of the question shouldn't be on topic on the site it started on.
(Sarcastic of course... I know SO meta says that even when that is the case, they want the answer on SO so then SO is the first link Google reports)
6:42 AM
@tpg2114 for those, you can leave a comment with the link and flag as too localized, or NaRQ, or something
@DavidZaslavsky Not really, there are tons of "better on site B" migrations that I've seen.
While the migrate dialog is under "off topic", it doesn't imply off topic
That's because a lot of moderators ignore the rule that you shouldn't migrate things that aren't off topic on your site
@DavidZaslavsky hmm, that's a rule?
Yep. That's the way migrations are supposed to work.
...at least that was my understanding, from way back
I'll just ask TL about this -- I'm quite sure it wasn't this way (i remember reading something on meta)
6:44 AM
Yeah, I think I've seen something about it too. But I don't think it's the intent of how the feature is supposed to be used.
Insomnia sucks
@tpg2114 watch TV!
I am, it's not helping... haha
@tpg2114 MOAR TV

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