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3:04 AM
@Shashaank JEE does not directly test concepts. It tries to check if students are able to think out of the box. As you said, someone who is thorough with concepts but does not have the ability to think fast is going to be failed by the JEE system.
@Shashaank I am not sure if that was a wrong tag. I gave JEE last year and I am giving once again this year. I don't know anything properly in UG physics (all blunt concepts; I can't even solve a problem properly). It is normal for JEE students to start studying topics which are not covered by the JEE syllabus. I always carry the Feynman Lectures on Physics wherever I go.
 
3:54 AM
@Yashas ok I gave it 2 years back. Only did the Physics section , did not even bother to turn to the chemistry section....But anyways , I feel it is blatantly useless and completely inappropriate for any one who likes Physics ( sorry but that is how I feel). This one would be your last year right i.e the April one.
 
This will be my last JEE Advanced attempt.
 
4:39 AM
@Yashas doesn't jee advanced have 5 min per problem? I think that is enough. But mains
 
@PhyMan It changes from year to year.
You get 3 minutes per problem on average.
 
oh okay i didn't know bout that
atleast the advanced problems are interesting, and you feel like solving them..... but the mains problems are too booring..
 
user228700
5:10 AM
@JohnR: Morning! :-)
 
Hi :-)
So what did you think of TTT?
 
user228700
Ugh, I wasn't able to finish it :-( There were quite a few interruptions in the middle, because of which I only started watching at 11.
 
user228700
...and by the time it was 1:15, I still had 1:30 hours to go.
 
user228700
So I went off to bed (and woke just now.)
 
The only occasions I'm awake at 11 p.m., let along 1:30 a.m., are if I'm out drinking with friends, and it usually leaves me a zombie the next morning!
 
user228700
5:14 AM
Haha! :-) I feel quite fresh this morning, actually.
 
The resilience of youth - enjoy it while it lasts :-)
 
user228700
Hehe :-) I've gots to book a train ticket in 15 minutes.
 
Going anywhere interesting?
 
user228700
It's a mad rush so hopefully, I make it!
 
Oh, you did say before. Back to Kerala?
 
user228700
5:15 AM
@JohnRennie No no, just Kerala.
 
user228700
Yep.
 
But this time you're doing more travelling? Visiting cities?
You did say something about it when we talked about taking your bicycle on the train, but I've forgotten the details.
 
user228700
Yeah. Although, we are staying at the village for a week or so :-(
 
user228700
After that, we'll be going to another house to meet my dad's brother and then to Munnar, I think.
 
user228700
Well, I hope anyway.
 
user228700
5:43 AM
ARGH, don't you just hate it when you're already in a mad rush to book tickets, you make the payment and everything and this happens:
 
user228700
 
5:57 AM
0
Q: To make successful question migrations, we need also proper tagging

peterhIf we vote a question to migrate away to a different SE site, there is also a non-trivial and lesser known requirement. The question needs to have a tag, which exists also on the target site. If it doesn't, the migration will be automatically rejected. This rule is one of the numerous obstacle...

 
@Kaumudi.H sounds annoying
 
user228700
6:28 AM
Yeah, no kidding!
 
Did you get your tickets in the end?
 
user228700
Nope.
 
user228700
I didn't make it yesterday either.
 
user228700
So now we're going to have to go by bus tomorrow.
 
:-( What now? Go to the station and buy them in person?
 
user228700
6:29 AM
No, bus tickets to Kerala are almost always available so I should be able to book them online today.
 
Ah. The train tickets are limited availability?
 
user228700
Very.
 
user228700
Back to finishing the Trilogy today, then...
 
user228700
@JohnR: Ooh, I'm meeting a computation neurologist today, BTW!
 
@Kaumudi.H Cool :-) How did that come about?
 
user228700
6:39 AM
My friend, who has just finished her 1st year in an integrated Science program at IISER (another premier institute for Science in India) is doing an internship with this prof. this summer (in IIT).
 
user228700
I went to meet her yesterday and told about the whole CN thing, which was when she told about him and asked me to tag along with her today, when she goes to ask about the details of her internship.
 
user228700
So I will. I'll ask about which undergraduate degree he thinks it's best to have; C.S or Electrical.
 
Excellent, that sounds as though it's going to be really interesting!
 
user228700
Yeah! I hope it will :-)
 
8:28 AM
@Kaumudi.H At the end of my first year in undergrad, I was completely torn between doing Computer Science and Physics. A bit of advice I was given by my physics supervisor was that they're similar enough that transferring from one to the other after the degree shouldn't be much of a problem (and they lead into the same sort of jobs anyway), so I should just do what I enjoyed most at the time
 
user228700
Uhh, OK, thanks...
 
(what I'm trying to say is that whatever subject you end up doing doesn't really determine anything afterwards, especially for two subjects that are so similar, although perhaps others will disagree)
 
Presumably CS carries the engineering cachet, which seems to count for a lot in India.
Aside from that I agree with Mithrandir. I don't think coding is that hard and if you're bright enough to get a physics degree you're bright enough to code for a living. In fact few of my friends who pay their mortgages by coding have CS degrees. In fact many have no degree.
 
sup doods
is 0celouvskyopoulo7 the same as 0celo?
namechange or duplicate account?
 
@Kenshin When I search '0celo' under users, the only one that comes up is 0celouvskyopoulo7, so it looks like it...
 
8:41 AM
ty Mith
I'm suprised people are still discussing his suspension given he was suspended from chat ages ago
 
no problem!
 
Should we refine the be nice policy of SE?
for example most countries don't say you can't offend or can't discriminate, but instead say you can't offend or discriminate against "protected attriubutes" such as age, race, gender etc.
perhaps we can outline protected attributes here that people should be careful about
In my view there are two ways to regulate, (1) Civil Code and (2) Common Law
We currently use a common law system here but it breaks down due to mods not being happy to discuss suspensions
 
The problem is that the moderation of chat is fundamentally authoritarian. The Daniel/Heather/Bernardo/Ryan axis don't like this, but they don't get to choose the rules. The SE community mods dictate policy and our mods have to enforce that, ideally as sensitively as possible.
 
So a civil code system would be better
@JohnRennie even if authoritarian, I have confidence the powers that be would agree with a consistent approach to moderation
so I don't believe codifying the rules of behaviour would be too difficult
 
If your father tells you to stop doing something you stop. If you start arguing with your dad you're likely to be sent to your room. The chat moderation is basically the same.
 
8:51 AM
yes I understand how it currently works
 
user228700
@Mithrandir24601 Ah, I see ur point. Thank you :-)
 
but this isn't optimal
 
The point is that it starts and ends with this. SE make the rules and we comply or leave - forcibly if necessary.
 
YEa that's like what I said in Meta
 
user228700
Sorry to interrupt but @JohnR: I quite like this Smeagol "person".
 
8:52 AM
the powerful make the rules
 
All the recent hoohah has basically been the aforementioned axis saying But Dad ...
 
lol
 
One of them got sent to their room for 30 days, the others will follow unless they toe the line. That's all there is to it.
@Kaumudi.H the guy who strangled his brother to get the ring?
 
user228700
Uhh, I haven't reached the brother part yet...
 
user228700
(Still watching TTT)
 
8:53 AM
@JohnRennie the problem for me is it is unclear where "the line" is
 
user228700
But yes, that guy.
 
@Kaumudi.H I don't think that's in the film. It's discussed in the books but I suspect it might be one of the things that had to be omitted to keep the film length to only ten hours! :-)
 
user228700
Oh, really? Hmm, they did say something about murder...
 
I am not on the side of the daniel/heather/bernardo/ryan axis tho
 
user228700
But nothing about a brother, no. It was hinted that he used to be a hobbit before but nothing more.
 
8:55 AM
But I think everyone can win with a civil code system
@Kaumudi.H have you seen frodo die yet
 
Smeagol is fundamentally a victim - he was corrupted by the ring as is everyone who covets the ring. So I have some sympathy for his position. But he is utterly amoral and will do whatever it takes to get the ring back.
 
user228700
-_- No. Thanks though.
 
user228700
@JohnRennie Yes, I agree.
 
user228700
I quite like this scene though:
 
8:56 AM
did you know lord of the rings is based on a greek tale
 
I can probably find the bit in the book if you want ...
 
The Ring of Gyges is a mythical magical artifact mentioned by the philosopher Plato in Book 2 of his Republic (2:359a–2:360d). It granted its owner the power to become invisible at will. Through the story of the ring, Republic considers whether an intelligent person would be moral if he did not have to fear being caught and punished for doing injustices. == The legends == Gyges of Lydia was a historical king, the founder of the Mermnad dynasty of Lydian kings. Various ancient works—the most well-known being The Histories of Herodotus—gave different accounts of the circumstances of his rise to power...
^what lord of the rings is based on
@Kaumudi.H that's my favourite bit of the film
 
user228700
@JohnRennie Oooh. If you're not busy and would like to, please do! :-) I'd be ever so grateful!
 
user228700
@Kenshin Same here perhaps :-) Haven't finished the movie though so not sure yet.
 
He had a friend called Déagol, of similar sort, sharper-eyed but not so quick and strong. On a time they took a boat and went down to the Gladden Fields, where there were great beds of iris and flowering reeds. There Sméagol got out and went nosing about the banks but Déagol sat in the boat and fished. Suddenly a great fish took his hook, and before he knew where he was, he was dragged out and down into the water, to the bottom. Then he let go of his line, for he thought he saw something shining in the river-bed; and holding his breath he grabbed at it.
From The Fellowship of the Ring, chapter 2, "The Shadow of the Past".
 
user228700
9:02 AM
Oh God...
 
user228700
That definitely changes things.
 
user228700
I had come to take pity on him for how the ring had corrupted his mind to the extent of insanity but this, wow...
 
user228700
Dammit.
 
@Kenshin I agree that the question should be asked, but my viewpoint is essentially that the 'be nice' policy is so good because it's so general, otherwise it would constantly have to be changing and adapting to match whatever is happening at that time in the SE sites
 
@Kaumudi.H but the ring was so bright and beautiful tho
 
9:04 AM
@JohnRennie There's definitely a scene in one of the films (RoTK?) about this, but it might have only been the extended edition
 
user228700
Oh, it is part of the movie!
 
@Mithrandir24601 yes the "be nice policy" is like a "common law" system, but for these to work one must understand the precidents. Unfortunately mods don't like discussing historic ation making this impossible
 
user228700
 
The implication is that the ring corrupted Sméagol. He is described as being a reasonably normal person before the incident.
 
user228700
@JohnRennie I find it a bit difficult to believe that the ring corrupted him on first sight...
 
9:05 AM
And yes, Sméagol is described (by Gandalf who is telling the story to Frodo) as "hobbit-kind"
 
@JohnRennie why did smeogal turn ugly
 
user228700
@Kenshin I disagree. His looks cuter when "ugly" :-P As a hobbit, not so much...
 
@Kenshin Ah, OK :/ I see the problem...
 
The book doesn't go into a lot of detail on Sméagol's back story, it just says (again, it's Gandalf telling this to Frodo):
The most inquisitive and curious-minded of that family was called Sméagol. He was interested in roots and beginnings; he dived into deep pools; he burrowed under trees and growing plants; he tunnelled into green mounds; and he ceased to look up at the hill-tops, or the leaves on trees, or the flowers opening in the air: his head and his eyes were downward.
There is no suggestion he was a villain before the incident with the ring.
 
user228700
Hmm, OK...
 
9:10 AM
@Kenshin His lifetime had been unnaturally extended by the ring. At the time of the LOTR story he was 589 years old. But this extension caused a gradual decay into the twisted form you see in the film.
 
i see ty @JohnRennie
 
user228700
@JohnRennie 589 oh God...
 
user228700
I like Smeagol as he is then.
 
user228700
It's clear that he's terribly regretful for the things that he did(/under the influence of the ring)
 
Well ...
From the book it's clear that he feels himself a victim. He regrets the fact he got corrupted by the ring but it's a self-indulgent regret and he feels it wasn't his fault and the world is to blame.
 
user228700
9:15 AM
Ah...
 
user228700
I pity him anyway. Perhaps not like but yes, he has my pity.
 
Bear in mind than Tolkien was a professor of English. He diodn't have a high regard for scientists, and Gollum is pretty much the archetype of the selfish scientist corrupted by his own foolishness.
 
user228700
A little bit, yeah, I guess...
 
Tolkien describes Seagol as inquisitive and curious-minded, which pretty much describes everyone here :-)
 
user228700
Ah, hmm :-)
 
9:18 AM
The whole story is basically a criticism of the industrial revolution and the technological progress that accompanied it.
 
user228700
Anyhoo, I gots to finish what I can of this movie before getting ready to meet the prof.!
 
why ru meeting a prof?
 
user228700
@JohnRennie Maybe I will have a clearer understanding of this when I finish the trilogy but that makes somes sense, yeah...
 
user228700
@Kenshin Scroll up/read the transcript for today :-)
 
aw k
 
user228700
9:20 AM
@JohnR: Even more interruptions so I wasn't able to finish it this morning, no :-(
 
@Kaumudi.H You really need to read the books to understand the underlying issues. The films are good, but they are necessarily shallow because you can't fit several thousand densely written pages into ten hours of film.
 
user228700
Dang.
 
user228700
They're too large! :-( With terrifyingly small font.
 
but books take too long to read
better to fill the mind with books of physics and computers
 
@Kaumudi.H The journey of a thousand miles ...
 
user228700
9:21 AM
:-/
 
user228700
It's OK, I will be content with this.
 
user228700
Alright then, I will see u all later. Bye!
 
tata
 
Geros Ilas
 
10:05 AM
@Kaumudi.H Speaking of the nerdwriter and movie music
this week's installment
You've seen Blade Runner, right?
 
10:32 AM
Guys, the Biot-Savart law gives the magnetic field of a steady line current:
$$
B(r)=\frac{\mu_0}{4\pi}\int\frac{I\times\hat r}{r^2}dl.
$$
Now according to Griffiths, for surface currents, the Biot-Savart law becomes
$$
B(r)=\frac{\mu_0}{4\pi}\int\frac{K(r)\times\hat r}{r^2}da,
$$
where $K$ is the surface current density, given by
$$
K=\frac{dI}{dl_\perp}=\sigma v.
$$
While the version of the formula for surface currents makes sense to me intuitively (you simply consider the current for each infinitesimal area through an infinitesimal width $dl_\perp$ that lies perpendicular to the flow), I
 
@dmckee @JohnRennie Ay of y'all around? When I have a foo.c and foo.h, if the function bar() in foo.h depends on stdlib.h should the include for it be in foo.h or foo.c? I know both will work, I'm asking if there's a standard or best practice
 
I would normally put includes in the .c file
 
@JohnRennie Yeah, I have them in the header right now, but I think it's not good for people reading the code
Alas, if they are in the .c, and the headers depend on a custom type, then I must include it in the .h no?
 
@BernardoMeurer as you say, it works both ways. But when I look at a .c file it's nice to see immediately what libraries it depends on.
 
Yeah, the problem is when the headers depend on a library already I guess
I'll leave it as-is, not that big a deal I guess
 
10:48 AM
If the .h file requires another .h file for it to be processed e.g. if it requires symbols defined in the other header then I'd probably do the #include in the .h file.
But I'd comment it to say why the include is being done there.
Most headers have a #ifndef pragma to stop them being processed twice, so it doesn't really matter.
 
(hm, never mind about my question above. I will just post in on the forum!)
 
@ShaVuklia I'm afraid electrodynamics was one of the few subjects at university that I really didn't like. It always seemed to me just an excuse for setting ridiculously complicated exam questions.
So unless it's a simple question I'm unlikely to be able to help much.
Come back to me when you're studying relativity :-)
 
@John no problem! I understand that!
haha, thanks, I definitely will then:)
 
@JohnRennie Do you want to do some physics?
I have another one of those problems that take forever and that I have no idea how to solve :^)
 
Oh go on then :-)
 
10:53 AM
Sweet, lemme translate it
A comet of mass $m$ describes an elyptical orbit around the Sun, with longer radius $a$. Keeping in mind that: The elypse equation in polar coordinates is $\frac{\epsilon d}{r}=1+\epsilon\cos\theta$, where $\epsilon$ is the excentricity of the elypse, and the the distance from the focus point to the [WORD I DO NOT KNOW]. The longer elyptical radius is $a=\frac{\epsilon d}{1-\epsilon^2}$, the area of the elypse is $A=\pi a b $, and that $b=a\sqrt{1-\epsilon^2}$
(More coming)
 
Is the word you don't know the directrix
 
What MOT orbital order should I choose while drawing MOT diagram for $O_2^{2+}$? Should I use the order which is used for elements below oxygen or the order which is used for elements above oxygen?
 
@JohnRennie Exactly
1) Show that the angular momentum $L$ of the comet in relation to the Sun (which is constant) verifies $L^2 = GM_s m^2(1-\epsilon^2)a$

2) Use Kepler's second law to show that the period $T$ of the comet's orbit verifies $\frac{\pi a b}{T}=\frac{L}{2m}$

3) Use Kepler's second law to demonstrate Kepler's third law.
 
If the center of the ellipse is taken as (0, 0), the equations of the directrix are $x = \pm \frac{a}{e}$ provided that the ellipse's major axis is along the x-axis.
 
Sweet Jesus! At least with programming I can understand the question! :-)
 
11:05 AM
@JohnRennie Yeah, I've failed this physics course already to be honest
I don't know why I still try
 
I feel like I've learned this stuff too, yet I don't know the answer either
 
@BernardoMeurer We get the problems like the one you shared in JEE :D
 
jee is some hard shit
 
For what it's worth, I hate my current physics course more than I hated chemistry last semester, and I hated chemistry.
 
how come you have so many different subjects? it is like a general programme in the natural sciences?
 
11:08 AM
@ShaVuklia I do Computer Engineering, but it's some bizarre program
 
oh, yea it does seem pretty bizarre:P
 
I'm in second semester and I have Programming, Computer Architecture, Multivariable Real Analysis, Mechanics and Waves, and Business
 
Business?! o0
 
Let's do a business
 
First semester I had Real Analysis, Linear Algebra, Digital Systems, Chemistry, and intro to Engineering
@Yashas I went to a class once, never again
There was no synergy
 
11:15 AM
@BernardoMeurer maybe you can use this: phy.duke.edu/~kolena/comet.html
 
@BernardoMeurer The vertex (near the sun) of the ellipse is at $(-a, 0)$. The the focus (the sun) is at $(-ae, 0)$. The total energy of any particle in an elliptical orbit is $-\frac{GMm}{2a}$. $L = mvr$ at the vertex as the tangent at the vertex is perpendicular to the focal chord from the vertex. $r = -a - (-ae) = -a(1 - e)$, $v$ can be calculated using energy conservation ($-\frac{GM}{2a} = -\frac{GM}{r} + \frac{1}{2}v^2$).
 
@ShaVuklia Nice resource! Thanks. This reminds me, did you ever listen to that band I linked on the email?
 
You get $v$ to be $\sqrt{\frac{GM(1 + e)}{a(1 - e)}}$
 
@Bernardo yes, I did actually, and I like their music a lot! Usually I only listen to 1 or 2 songs from a band/artist, but I finished their entire album "Fantomas" when you mentioned them:)
 
$L = mvr = ma(1 - e) \sqrt{\frac{GM(1 + e)}{a(1 - e)}} = m \sqrt{GMa(1 - e)(1 + e)} = m \sqrt{GMa(1 - e^2)}$

$L^2 = GMm^2a(1- e^2)$
 
11:19 AM
@ShaVuklia Nice! Glad you liked it :)
@Yashas Good lord
You're the new ACM
 
Hey!
 
hi @ACurious
 
@ACuriousMind Not my fault that you don't help anymore
 
Hey @ACuriousMind
 
@Yashas What's "The vertex of the elypse"?
 
11:20 AM
Why does Rovelli write 3D coordinates as $\vec \tau$
 
:|
 
That is very confusing
 
@BernardoMeurer lol I was thinking the same:P
 
NEVERMIND
I already know
We just call it something else in Portuguese
 
I yea me too now. I just googled it
I think we call it perihelion or something like that
like "close to the sun"
 
11:21 AM
@Yashas Why is that the focus?
 
@BernardoMeurer Ugh, I've got a terrible hangover and am not in shape to help anyone right now
 
@ACuriousMind maybe physics is a good way to get over the hangover :P
 
Yashas is going places
 
$a$ = semimajor axis
 
11:22 AM
charges dropped against Jullian
what do you brains make of this
 
@BernardoMeurer which one? The objects orbit one of the focus (when $M>>> m$) of the ellipse.
 
@ACuriousMind YOU ARE ALWAYS DRUNK
 
@ShaVuklia Trust me, it's not
 
Defining the spin connection sounds like an arse and a half
 
You're worse than me!
 
11:24 AM
@BernardoMeurer That was the first time I drank since last Friday, so no :P
 
Jim
woo! May two-four weekend!
 
You start from the frame bundle, then go to the orthonormal frame bundle, then the oriented orthonormal bundle, then the Clifford bundle and finally the associated bundle
 
0
Q: Weird trick for solving surface integral?

Lozansky Calculate the flow of the vector field $$\mathbf{A} = \nabla \dfrac{\mathbf{a}\cdot\mathbf{r}}{r^3}$$ from a cube with side length $1$, centered at origin and with one space diagonal parallel with the constant vector $\mathbf{a}$. Attempted solution Let the $z$-axis run parallel to $\mathb...

 
@Yashas I mean the focus of the sun, why is it $(-ae, 0)$
 
Drunk me just has very poor judgement of when to stop drinking
 
Jim
11:25 AM
@ACuriousMind But that's a problem sober you has to deal with. It's not drunk you's problem
 
maybe drunk you has the better judgement
 
@ACuriousMind Come to Geneva the first weekend of June
 
@Jim I fear that's precisely my thought process
 
I'll be there chilling
 
You have to go back to the definition of conic sections. The ratio of the distance of any point on the conic to the focus and the distance of any point on the conic is equal to $e$.
When $0 < e < 1$, the conic section formed is an ellipse.
 
11:26 AM
@Yashas I read that message and all my brain capture was "Just trust the guy alright, he wouldn't lie"
 
If you screw with the equations for a while, you will get $e^2 = 1 - \frac{b^2}{a^2}$ where $a$ is the length of the semi-major axis and $b$ is the length of the semi-minor axis. You can derive everything else easily from ^
 
Jim
for anyone interested in further insight into my culture, this weekend is our national holiday that is traditionally celebrated by getting a case of 24 beers and getting smashed with your friends
has to be 24 beers. Can't be another number
 
@BernardoMeurer I can't, already got plans for that weekend
@Jim What are you celebrating, exactly?
I guess our national holiday is reunification day
 
Jim
@ACuriousMind Well, officially, it's "Victoria day", which is celebrating Queen Victoria's birthday or something like that. But really, it's more like celebrating the end of winter by drinking beer. A two-four on May two-four
 
@BernardoMeurer www.askiitians.com/iit-jee-coordinate-geometry/ellipse.aspx
 
11:30 AM
@Jim Hehe. I'd like to celebrate the end of winter but it's cold and raining here right now
 
@ACuriousMind :( </3
 
We actually wanted to have a barbecue today, but I don't think that's gonna happen with this weather
 
@Yashas What about 2) ? I don't even know Kepler's law
 
I don't remember which law is which :D
 
Jim
Here you go, a definition of May two-four that adequately describes it
 
11:32 AM
@ACuriousMind I'm going to fail physics and it's all your fault
Because you're always drunk
 
I'm not sure hungover me cares :P
 
I remember that formula actually, $T = 2\pi \sqrt{\frac{a^3}{GM}}$
 
Drunk me will send you an apology, I guess
 
2) Use Kepler's second law to show that the period T of the comet's orbit verifies $\frac{\pi a b}{T}=\frac{L}{2m}$
 
I don't understand the second question. Kepler's law itself relates radius to the time period. How do you show Kepler's law using Kepler's law?
 
11:34 AM
I think Kepler's second law is the one where you're not supposed to walk under ladders because it's bad luck
2
 
Ohhhh!
Kepler's law only tells that $T^2$ is proportional to $a^3$
You probably need to plug in the numbers and find the constant.
 
Jim
@Yashas that's the third law
 
@Jim What's the second law? :P
Luckily, JEE does not test how much students remember :P
Otherwise, I would fail :P
 
Jim
law #2 is that objects in orbits sweep out equal areas in equal times
 
Yea, I just googled.
@BernardoMeurer The second law is just a restatement of conservation of angular momentum.
 
The area swept per unit time is equal to $\frac{L}{2m}$ if I remember correctly.
 
Jim
I know the laws by heart. <-- Space engineer specializing in orbits
 
Guardians of the Galaxy 2 taught me one thing: Never, ever trust your biological father if he is a boltzmann brain
 
As L is constant, area swept per unit time is constant.
 
@Jim Save me
 
Jim
11:36 AM
@ACuriousMind amazing!
 
Corollary: Never trust any boltzmann brains. They are self-serving apatheic bastards
 
Jim
@BernardoMeurer I help those who help themselves
 
@Jim I can help myself to some beer if that's what you're saying
 
Jim
@Secret what about Boltzmann's brain?
@BernardoMeurer I'll definitely help you, in that case
get it? in that "case"
 
11:38 AM
The way Ego in guardians of the galaxy 2 when he talked about his past is basically he starts as a brain floatin in space, thus fitting the definition of a boltzmann brain
 
@Yashas Back at it, I don't see how we're going to connect these things
 
Jim
@Secret it had to happen somewhere; it wasn't forbidden
 
@Secret boltzman's brains usually odn' thave powers hto
 
@BernardoMeurer You need to find the areal velocity.
It is now an ellipse problem again.
 
@Kenshin Gotta be glad that our world is not very supernatural
 
Jim
11:40 AM
@Kenshin Stefan brains?
 
Areal velocity= L/2m; now you need to find out the areal velocity
 
Jim
Q: is any part of our natural world supernatural? A: ..... Okay, first I'm going to have to explain to you how the prefix "super-" works.
 
@Yashas I'm solving 3) first, it's just equation finangling
 
Jim
@BernardoMeurer (2) has some angling in it too. Not sure if it's full on FINangling though
 
I got the 2). You have to do draw the ellipse, the radius and find the area swept in time dt. You then have to equate it with L/2m.
 
11:44 AM
Sigh, fuck my life.I should have gone for CS
WHY DID NO ONE WARN ME TO STAY AWAY FROM ENGINEERING
 
Jim
it's a trap!
 
It so is
Engineering is a meme
 
@BernardoMeurer I think the question 2 asked for verification, not proof. I think you need to find the area of the half the ellipse, i.e: $\pi ab/2$ and then divide that by $T/2$ to get the area swept. I think that is what they want.
 
@BalarkaSen Is a manifold its own trivial principal bundle
 
M is a trivial group bundle over M, sure
 
11:47 AM
$M \times \{I\}$ with structure group $I$
 
@BernardoMeurer That is easier. area swept per unit time = $\frac{\pi ab}{T}$; Kepler's law says it remains constant. Now you have to substitute for $b$ and $T$. $T = 2\pi \sqrt{\frac{a^3}{GM}}$ and $b = a\sqrt{1-e^2}$. After some manipulation (multiply and divide by $m$), you get L (you know this from question (1)) at the top and $2m$ remains in the denominator. This is waaaaaaaaaay easier. The question does not ask you to prove so this should be enuf.
 
@Yashas Okay, just finished 3, now to 2
@Yashas T there is the time or the period?
Period
so wait
 
time period
 
What's $\frac{dA}{dt}$?
 
the total area of ellipse is $\pi ab$ (simple parametric integral will give that answer)
the commet makes a full round around the ellipse in one time period
the area swept per unit time remains constant (Kepler's law)
so you can substitute any case and find $\frac{dA}{dt}$
@BernardoMeurer area swept per unit time
For simplicity, you take the case where the comet completes one full cycle.
 

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