The h Bar - 2016-12-03 (page 1 of 4)

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12:51 AM

@BernardMeurer heh. He's fine.

@DanielSank :)

1:27 AM

Apparently 2D Alcubierre metric also has divergent vacuum

Why is physics so boring

1:51 AM

@Slereah Integrate Thomae's function for me plox

Using only it's Riemann integrability

1 star = 1 prayer

user228700

2:42 AM

For whom are we praying? U? xD

@Kaumudi My soul

@BernardMeurer sent your package, finally.

user228700

What's up w/ ur soul, man?

The Universe has been trying to prevent it.

@DanielSank WOOHOO

@DanielSank I need integration help

<3

2:51 AM

@BernardMeurer k

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Oh for god's sake

wat?

U mad, bro?

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How do I integrate this perversity @DanielSank

Call Amit

Ah, using only it's Riemann-integrability

Aya! I don't do problems like that.

Lol

That's why I told you to call Amit

He's the secret CEO of Geegle

3:07 AM

:|

Dude... I sent you awesome hat, exclusive Google stickers, and a special hard drive...

You should show some respect.

@DanielSank How much more respect can I show? You got married already there's only so much I can do

Dude whatever.

I get you all this cool stuff and all you get me is attitude.

@DanielSank <3

What did you expect, you're the adult

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@JohnRennie Cower in fear as my kindle takes down your server MUAHAHAHA

user228700

3:31 AM

I've a quick question about miscibility and entropy again. A few days ago, JR said this:

user228700

> "The fact that liquids interact doesn't imply that interaction is necessary for mixing."

user228700

This has lead me to wonder if there are liquids, which have a low enough $\Delta H$ for the mixing to occur, but have a very low $\Delta S$ so that the process of mixing becomes non-spontaneous. Are there..?

Not sure.

@BernardMeurer Isn't the integral zero?

The irrationals are dense... something something.

Paging @Danu @ACuriousMind @0celo7

user228700

I'm starting to feel like my question is sort of dumb. Nvm.

3:55 AM

@DanielSank Yes, it's 0. But idk how to prove it

I can see that since the set of discontinuities is $\mathbb Q$, which is countable, and therefore has measure zero, the function is Riemann integrable, but idk how to calculate the integral

@Kaumudi of course there are

@Kaumudi put oil and water together, they won't mix

Even though the entropy change would be positive, the enthalpy would be endothermic and thus the change in gibbs would be negative

therefore this process wouldn't be spontaneous

oh u mean an exothermic process but with negative entropy?

wont happen because mixing will always increase entropy

user228700

4:16 AM

Yes, this is what I meant.

user228700

@Mew I realized this, which is why I said "Nvm".

user228700

When are u gonna watch the movie, BTW?

in a few hours

4:52 AM

@Mew if change in gibbs is negative then it should be spontaneous

@koolman indeed\

@koolman in the example of water/oil, the endothermic enthalpy change (+ve gibbs change) outweighs the increase in entropy (which contributes -TdS, i.e. a -ve gibb change)

thus the change in gibbs free energy is +ve and thus not spontanous

that's why water and oil doesn't mix

user228700

@Mew OK.

user228700

I need your help.

ok

@Kaumudi I have a theory of human happiness an dmotivation

do u want to know it?

user228700

@Mew After a little time? I'm taking a 5 minute break now...

5:03 AM

it's superior to Maslows idea

and simpler

user228700

Hmm, I see. Why don't u write it down properly? Like, an essay?

here it is:

user228700

I will read it in awhile OK?

Happiness = when one has the confidence that they can overcome obstacles/threats

Pleasure = Feeling when an obstacle/threat is overcome

So why does one enjoy learning? Because learning increases your confidence in being able to overcome future threats

user228700

Hmm. I will respond after I think about it.

5:05 AM

@Mew i see

user228700

Dammit, @Mew, I was going to ask u about Star Wars! Now I've to get back to my book —.— (Jk :-) I will think about ur theory)

wat about starwars tho

i'm a fast typer

user228700

If u're around in 45 mins, I'll ask u :-P

maybe, mayb enot

user228700

OK, we'll see in 45 mins :-)

5:07 AM

yeah i might be getting ready for the movie

user228700

Ohh, OK. Well, two years ago, I bought the second book of the thrawn trilogy.

ok sorry i don't know about that

user228700

Oh, u dunno about the books? OK, will ask Sir (:-P) John!

yeah i don't know about the books just the films

user228700

Have fun at the movie! It's 3-D and everything! (Said the toddler :-P)

5:09 AM

esp. 1 2 and 3

user228700

I see.

I'm seeing the 2d Version tho

user228700

Ohh.

yeah some sessions are 2d and some 3d

I always go the 2d

user228700

I bet it'll be just as great :-) Have fun! I'll go when it's about midnight for u.

5:10 AM

yeah

user228700

Bye!

byeE!

1 hour later…

6:23 AM

@BernardMeurer Using Kindles for a DOS attack. Now there's an interesting possibility :-)

@JohnRennie why $SF_6$ is more stable than $TeF_6$

17

A: Why are silicon-silicon bonds weak?

At the risk of oversimplifying: bonds form because the bonding electrons can lower their energy by being attracted to both nuclei. Take the simplest possible example of H$_2$. The electron density looks like: (image from Hyperphysics). The formation of the H-H bond increases the electron dens...

The same argument applies to the Te atom in $TeF_6$

Ty

7:01 AM

[Dream] While I don't have recurring dreams yet, I do have scenes within a dream repeated many times and rewound many times, and completely dream generated chaarcters to recur in later dreams

By "completely dream generated characters", they are people which does not based on any people I know of

user228700

@JohnRennie: Morning sir :-)

Morning :-)

user228700

I'm reading our conversations and making notes. Boy, is this tedious.

When are you going to see the film?

user228700

In about...6 hours :-) A novelization will be published-dyou think u might give it a go?

7:11 AM

Possibly. Novelisations of films are rarely that good. In any case the film is based on a novella JKR wrote for charity a few years ago. So I'd be reading the book of the film of the book :-)

user228700

Not really...

user228700

That book is merely a textbook. JKR wrote a brand new screenplay for the movie, which is going to be published as the novelization.

user228700

The textbook certainly doesn't feature Grindelwald :-)

@Kaumudi True :-)

Anyhow, everyone says it's a brilliant film. I might even end up taking my niece to see it.

user228700

God, I hope it's great. I'm very excited :-D

7:18 AM

:-)

user228700

@JohnRennie Awesome!

I heard that 2017 is a big year for scifi movies, with at least 13 new scifi movies coming up. But what makes 2017 so attractive for scifi?

I love that feeling of having something exciting to look forward to.

user228700

Yes, that's definitely one of my favorite feelings :-)

user228700

Will u be around in 10 minutes? I need to ask about Star Wars.

7:25 AM

Yes, I'm around most of the morning.

I'm not an expert on Stars Wars though ...

I did watch the original three films back when they were released, but I haven't seen parts 1-3 and I haven't read any of the novelisations.

user228700

I see.

user228700

I've a quick question about Raoult's law first. Dyou mind..?

user228700

No, nvm.

No, that's fine. Please ask ...

user228700

:-P I'm afraid I figured it out...

7:39 AM

@Kaumudi Good, that's always the best way to learn stuff :-)

user228700

:-) So the question is, if I read the Thrawn trilogy without watching any of the movies, will I understand?

Yes, you should be fine with those books.

The books will make references to events you don't know about, but that will be peripheral to the main story.

user228700

Ohh. In that case, I'll go ahead and watch the movies first. Which ones are they? (Sheesh. Making plans for next summer already :-P)

You should be aware that those books aren't great literature. Timothy Zahn is a competent writer, but not amongst the greats.

user228700

So...it might not be worth it?

7:43 AM

I'm always reluctant to advise people on their reading because different people like different books ...

user228700

Sigh. The idiot that I am, I bought the second book in the trilogy by mistake and then I started reading and realized it was the second book in a trilogy. This was summer, last year.

user228700

It's been sitting on my shelf for such a long time now. I sort of feel obligated to read it sometime :-P And it's the second book, so I have to read the first and then if I like it, maybe the last one too.

Do you specifically want to read Star Wars books, or are you generally looking for great SF books?

user228700

@JohnRennie That is true...

user228700

@JohnRennie The former. Sometimes I feel fomo regarding the Star Wars fandom :-P

user228700

7:47 AM

Can u tell me which movies I need to watch before reading it?

I'd watch the films first. Have you got a DVD player? I've probably got copies of the DVDs lying unused somewhere.

user228700

How on Earth am I going to be able to borrow your DVDs?!

I assume India has a postal service :-)

user228700

U were the one who said this:

user228700

Nov 24 at 11:41, by John Rennie

@Kaumudi gosh no, don't do that. Mailing costs from India to the UK would be prohibitive.

user228700

7:50 AM

It's not worth the effort :-) I'm sure I'd be able to get them somewhere here/download (? :-P) them? I just need to know which ones...

Yes for a tin of gulab jaman. I doubt mailing three dvds would cost more than a letter.

Anyhow, see:

Star Wars is an American epic space opera franchise, centered on a film series created by George Lucas. It depicts the adventures of various characters "a long time ago in a galaxy far, far away". The franchise began in 1977 with the release of the film Star Wars (subtitled Episode IV: A New Hope in 1981), by 20th Century Fox, which became a worldwide pop culture phenomenon. It was followed by the similarly successful sequels The Empire Strikes Back (1980) and Return of the Jedi (1983); these three films constitute the original Star Wars trilogy (Episodes IV–VI). A prequel trilogy (Episodes I–III...

The original three films are A New Hope, The Empire Strikes Back and Return of the Jedi.

user228700

I get a little dizzy just reading the first few lines. That's why I asked you! :-P

They are now referred to as episodes 4 to 6, because of the three prequel films.

user228700

Okay. And then there have been sequels 7, 8, 9...

user228700

What's an anthology film?

7:53 AM

The only sequel so far is The Force Awakens, which is episode 7.

Episode 8 is planned for some time in the next year or two, though I don't know if it has a title yet.

user228700

Ohh, okay.

There is a (very good) film called Rogue One, which is set in the same universe but isn't part of the main storyline.

user228700

is? Has it been released yet?

Can you download films? If so I might hypothetically be able to put copies on my server for you.

user228700

I think so...will u be here June of next year? :-P

7:56 AM

@Kaumudi Unless my lifespan turns out to be a lot shorter than I expected I will still be around in June :-)

But you could download them now of course. You don't have to wait until June.

user228700

:-) I'll try and watch them in June, then.

user228700

@JohnRennie Yeah, but my laptop's dead.

user228700

Around June, I'll get one for college and then I'll be able to download them.

Ah, OK. You'd be welcome to one of the laptops in my pile, but amazingly it's forbidden to post laptops to India.

user228700

Haha :-P

user228700

7:58 AM

You're very very kind to offer sir, thanks very much :-)

Unless you know someone who is coming to the UK and could bring a laptop back with them. I guess that's unlikely ...

user228700

Very. I don't personally know anybody in the UK/going to the UK except u :-P

Incidentally Rogue One is released in the UK on Dec 14th (I think)

user228700

Ohh, I see.

user228700

Will u go?

8:02 AM

Maybe ...

user228700

Okay :-) I'm starving and lunch is ready!

I tend to only go to films when someone drags me along. Typically when my niece wants to see a film and her parents are too busy to take her.

See you after lunch. I should probably do some work now anyway.

user228700

Yes, u've told me :-)

user228700

@JohnRennie :-P OK.

8:23 AM

@JohnRennie do you know about errors in practical physics

I have a question on that

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Have any idea , how to solve it

@koolman: I have to work for the next hour or so. Sorry :-(

@JohnRennie no problem

koolman, which part of this question you have trouble with (because to calculate, you basically need to substitute the numbers in, and use suitable error propagation formulae)?

@Secret in finding error

According to me it should be 0.7

But the answer is option a

9:10 AM

@Kaumudi I had very good Chinese for dinner.

There is a small restaurant across the street from my lab.

Sauteed greens with garlic, dumplings, and some spicy stuff.

@JohnRennie how do you know Rogue One is good?!

Koolman: OK I am not sure what I have done wrong but I get a ridiculously small number for the error: 1.41682E-05
Might have the try again later

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user228700

@DanielSank I see :-) Unfortunately, I've never had Chinese food :-(

9:26 AM

@DanielSank Dumplings are often taste good for chinese food

@DanielSank It just is. OK!!! :-)

user228700

:-| Hmm....

Given 2017 is a year of scifi movies, any titles you guys want to see in particular?

user228700

Nope. FBAWTFT will be the last movie I see till June of next year.

9:42 AM

2

Q: What does zero heat capacity mean?

What is the physical meaning of 0 heat capacity? Does it mean that no matter how much heat I put in, I cannot raise the temperature? If so, does this means that if a system is at absolute zero, it cannot be raised in temperature?

Stuck at ground state

10:20 AM

@JohnRennie can u give me rogue one pls

I can't I'm afraid.

but u said u could give it to Kaumu

10:37 AM

I offered to mail K the DVDs of the original trilogy.

is? Has it been released yet?

John Rennie
John Rennie
Can you download films? If so I might hypothetically be able to put copies on my server for you.

To be honest I'm not really that interested in films. I much prefer books. Any of us long time IT guys know whereabouts in the darker corners of the Internet interesting things can be found, but I rarely look. That isn't because I'm especially virtuous - I'm just not interested :-)

oh k

the dark coners sounds scarty

scary

Once you go off piste you certainly need to tread carefully ...

@Secret ohk

@Secret i have got something but could not understand this

2

Q: Calculation of error in focal length?

$u=-10cm$ $v=10cm$ Using the formula the focal length is 5 cm. But how do I get the fractional error in focal length when neither $\Delta u$ nor $\Delta v$ are specified? The options given are A. (0.05±0.05) cm B. (0.05±0.10) cm C. (5.00±0.05) cm D. (5.00±0.10) cm

homework-and-exercises geometric-optics error-analysis

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10:54 AM

the errors given in that answer are taken from the smallest graduation (which is specified in the question in your case)

he then use the common error propagation rule that if two quantity multiply or divide, the fractional error is the sum of the fraction error of the quantities

Solenodon Paradoxus

Hello guys

Hi @SolenodonParadoxus

u look like ur from Fantastic Beasts and Where to Find Them

Solenodon Paradoxus

I can assure you I'm quite real and also quite venomous

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