@DanielSank I do not disagree with what you said, but I think it's unfair to judge the position of human tragedy we are at by war and number of deaths anymore. The thing going on right now is a cold, in-built, social degradation. Not saying it's been there before, but this form of degeneration is new, because the world had not seen two world wars, a cold war, capitalist society at it's full glory and a technological boom all at once in a century before.

@BalarkaSen I'm not sure what you're saying.

I really feel this is more important than mass murders or authoritarian oppression at this point.

You say there is a degradation now that did not exist previously?

Yes.

Please explain.

Please explain to me how we have "social degradation" in a country where black and white people marry and have children.

Compare this, please, to the world history in which slavery was normal.

That's a one dimensional view. You're comparing two different beasts; I'm talking of an economical aspect of society, namely, post-consumerism.

...or where women were kept out of huge swaths of society by explicit social contract.

@BalarkaSen You actually haven't said anything specific yet.

But I will continue to give specific examples until you give me one.

You will please explain how post-consumerism is more of a degradation than the Russia which had serfs.

Consider the huge economical unstability caused by capitalism after cold war, say. This did not exist before, simply because industrial revolution happened in the 17th century and took the form of colonization in 18-19th century and materialized as inter-continental wars in the 20th century. This is actually important, because the Chinese tragedy in Mao's regime was a consequence of this. The class struggle is what caused the cannibalization in China.

@DanielSank I was about to, but had to stop by in the middle and mention that your view of social degeneration is not what I had in mind.

This is a much more implicit issue, which is in my opinion bound to be rooted into the postmodern man's psyche because of the current economy.

@BalarkaSen But how is that worse than what came before?

Instant, world-wide, and continuous media coverage has contributed to a larger awareness of every kind of tragic event.

^

@BalarkaSen I'm still not sure what comparison you are making.

One of the results of that is that even in places where violent crime has been steadily down for decades many people are convinced that they are living in a raging pit of anarchy.

My guess would be that the Russian serfs and the middle English peasants would flock to modern society where the location of their birth doesn't determine what they're allowed to do with their lives.

@dmckee True, but I think that's not what BalarkaSen is getting at.

And the human brain being what it is people can be very, very hard to convince of this.

Humans judge the quality of their lives by the quality of the lives of those around them. NB: we very often overestimate the quality of the lives of people around us.

It's amazing how often we think our neighbor is siting pretty, while he/she is actually in the midst of financial crisis, emotional turmoil, and health problems that we simply don't know about.

@BalarkaSen Er ... you do know about the raging tormoil of the business cycle throughout the 19th century, right. Ever 15 to 20 year saw a economic shock that broke banks and put people out of work in droves.

The great depression was the culmination of that.

Now, the banks that broke were mostly locals so this town was effect by its back going bust while their neighbors ten miles down the road might be doing OK.

@DanielSank Because common, normal people of Red China, peasants, killed and ate people, their neighbors due to some buried down idea of economical unstability. Not a political power of some sort, or oppression of the authority or a king. Hoards of people killed other hoards and ate their limbs until it could not be stopped and the party had to position armies to stop that. This dystopian frenzy is caused by the modern form of capitalism.

Can you really give me examples of mass cannibalism happening before this incident in history?

Where it was not because of famine, say

I'm confused for a few reasons:

1) I think you're suggesting that cannabilism is somehow very bad and I don't know why I should agree.

2) You are suggesting that the Chinese ate each other out of fear, but that they were not in a famine. Is this correct?

3) You are using a single incident of social craziness, in particular in an extremely unstable country at a particularly volitile point in their history, to show that modern capitalism is responsible for some kind of global social degradation. I find this somewhat weak. Can you give more examples?

1) Mass cannibalism is definitely very high on my list than political oppression or wars or stuff like that, simply because it's an act which shows the most terrible form dehumanization, caused by human hatred.

Wait wait wait

2) No, out of hatred. Evidence, including lots and lots of interviews unearthed very recently, support this.

Why is cannabilism worse than, say, what Ghengis Kahn did?

He killed a huge fraction of the world population out of what I would almost call boredom. How is that less dehumanizing than what the Chinese did to each other?

Hey @BalarkaSen, want to start a separate room for this? I'm really interested but I don't want to hog up hbar. Alternatively we can stay here until someone complains.

@DanielSank wrt that, there is some fairly recent scientific study of mass casualties due to war, its in major decline. eg wired.co.uk/article/… however the modern media, cyber-juiced-amped-up, is an entirely new phenomenon in human history...

@DanielSank Oh I am surprised you are interested, I'm just throwing around some thoughts of mine (a non-expert) which I consider to be interesting. But, uh, sure, maybe we could talk elsewhere.

(I do have answers to your last and 3rd question, I think, but I fear bringing up silly sounding points and it takes me some time to put thought to word)

@Blue What exactly do you think is circular?

logic is circular. that isn't the point. the point is that it is self-consistent.

@LeakyNun It's not even necessarily circular, it's just that the non-circular version is unmotivated. You say 'I'm calling this thing work—don't ask why", then define energy as the capacity to do work, show the work energy theorem, and bootstrap conservation from there.

@Blue The definition of energy is the Noether charge associated to a time-independent Lagrangian.

@BalarkaSen chat.stackexchange.com/rooms/64025/post-consumerism

@0celóñe7 Sure. But not until you know enough physics. You have to start somewhere.

@Blue just define energy or work as $\int \vec F \cdot \ \mathrm d\vec s$

@DanielSank re genghis kahn, also dont know if youve heard this, amazing factoid. 1/200 men are descendants blogs.discovermagazine.com/gnxp/2010/08/… the ulterior reality is that (no delicate way to put this...) he was probably the worlds most prolific rapist...

@vzn Yeah

@Blue energy is the integral of force vector dotted with the differential of the displacement vector

@Blue difference in energy / energy provided / energy given / energy required / etc.

@DanielSank lol, no historian suggests genghis khan was motivated by "boredom"...

@vzn No seriously then. What?

They went around destroying cities, leaving nothing behind.

They didn't conquer. They just destroyed everything.

@DanielSank dont argue with any of that, but how does any of it relate to boredom? poor choice of word(s) if you ask me

They felt people who lived in cities were weak and inferior and deserved killing

@Blue yes, which is why they have the same unit

I like to think of work as relative and energy as absolute, i.e. with a reference

people rolling in the deep here

@0celóñe7 ...why?

so I should have defined work first @Blue

@Blue This is not my field but you should note that Noether's work clarified this vague definition.

What could possibly motivate someone to wake up and say "I have sheep and grassland to graze them. I have tents and water. I'm totally fine. But you know, I think I'll erradicate a society anyway."

@Blue then again, if you can tell me what the hell a lagrangian really is...

@BalarkaSen agree with your general idea/ theme/ thesis of "social degradation" connected with hypercapitalism but notice its inherently not really nec violent/ fatal. some of this was recently (semifamously) analyzed by piketty eg newyorker.com/news/john-cassidy/…

"I will not take their city. I don't want their walls for shelter. I just want them dead and their structures gone."

@0celóñe7 It's a thing you differentiate to get equations of motion.

Bam.

I wouldn't call that boredom either. If at all, there have to be strong motivations behind his (and his successors') expeditions

@DanielSank yes, but when you try to do friction or fluids you get insane things

@Blue is my answer satisfactory?

Your definition isn't wrong, but it's not good

@DanielSank it seems not doubtful that genghis kahn was a psychopath, which is now a highly studied psychological area, but they are generally not associated with doing things out of boredom... it looks like his major motivation was (not uncommonly) drive for wealth + power (those things are interconnected...)

@DanielSank I can't point to a lagrangian in the night sky, figuratively speaking

I don't know what the physical interpretation is, maybe there isn't one

A wild Langrarian appeared! Go Newtonian mechanics. Newtonian mechanics used: Cartesian Coordinates.

It's super effective...

@CooperCape use Euler-Lagrange, that will be effective :3

Sounds like a TM to me... I'll see if it's in the local DifferentialMart

@Blue weeeelllll

Thermodynamics isn't really physics

F.dr is for, say, one particle

Or a system of a few particles

@0celóñe7 O_O'' why not?

@Blue In the case of transfer by conduction it is very easy and clear: the forces involved are inter-molecular forces and the paths over which they are applied are the motions of the molecules. That it's only amenable to statistical treatment doesn't make it any less true.

Covection moved the energy around by motion, but on- and off-loads it by one of the other mechanisms.

@Sanya because of what @dmckee Just said

For radiation you can work it several ways, but the classical E&M one involves the electromagnetic forces between light waves and matter.

@0celóñe7 that doesn't provide any reason

ʅ（◞‿◟）ʃ

@LeakyNun This is incorrect. I the building-from-the-ground classical treatment energy is a fairly abstract concept along the lines of 'any property of a object or system giving it the ability to do work' and is assigned the quantity of the work that it can do. But 'energy' is not defined by the path integration for force-dot-displacement–that's work.

Of course, once you have the infrastructure the Noetherian definition is very pretty.

@vzn If it were wealth, why did he destroy cities instead of conquering them?

@DanielSank not an expert on this, but he seems to generally fit the profile of a (hyper-)conquistadore. note that "scads of concubines" were part of his wealth/ power/ "motivation"... my understanding, he apparently liked to destroy cities that defied him as "brutal examples" (to others)...

@dmckee I managed to be useful today. I tracked down RF noise in the PMTs and I correctly diagnosed an unexpected histogram of PMT output data with the suggestion of "maybe we should look at what the waveforms look like"

@Blue Physicists never talk about 'heat contained in the system'.

Heat, like work represents a transfer or transformation of energy.

That said, chemists do talk about contained heat energy. A physicist would call that 'internal energy' or 'thermal energy'.

@DanielSank Maybe a demonstration of his political/military power? That's mainly why Tartars attacked and plunged Russia, too, say.

I have to say, that this particular divergence of terminology may cause more confusion than any other in the physical science.

I don't think boredom is a satisfactory reason, but I also do not know of the events well enough to argue.

@dmckee Bold claim, sir.

@Blue do you want to do a study group

@Blue abstract algebra

Could someone please come to this question? Maybe I really am misunderstanding stuff, but it just seems like he's willfully rejecting answers that say "no"

@Blue this stuff seems pretty boring

algebra is a slog

what homework?

i.imgur.com/QOByPwW.gifv

@DanielSank do you browse reddit

@0celóñe7 what do you think?

@DanielSank I have no idea.

Yes I do.

I have subscriptions set up so that my front page is stuff I care about.

Metroid, Smash bros, cute animals, octopuses, and a few other things.

I used to participate in r/askscience, but it became too discouraging.

The format here is better.

@BalarkaSen Learning baby field theory

@AccidentalFourierTransform I'm in Mexico at the moment. So yes.

your peoples OK?

↑ physics angle: lubos motl, john baez, scott aaronson all blogging on it, links enclosed

i'm having trouble with a physics problem, if anyone would be willing to give a hand:

> Consider a too-small space habitat that consists of a rotating cylinder of radius 4 m. If a man standing inside is 2 m tall and his feet are at 1 g, what is the g force at the elevation of his head?

@heather I don't get it

is he perpendicular to the rotation axis?

@Blue I'm assuming the acceleration of the feet is 1g...@heather is the man completely rigid

the cylinder is rotating like a wheel would roll, and the man is standing in the wheel, so yes, I think so @0celóñe7

what's going on here

and yes, I think we can assume the man is rigid.

@heather you will probably get two answers depending on if he's pointing up or down

that will mean he's further/closer to the center

he's pointing head toward the center.

his head is, at least

@heather oh, so the acceleration of the boundary of the drum (r=4m) is 1g

compute omega from that

then compute the acceleration at 2m

I think i get it...one moment

okay, no, i don't get it. centripetal force is given by F=mv^2/r

i don't see how there's enough information

@heather In that equation $v$ is the tangential velocity, and of course, the head has a different tangential velocity than the feet.

I said find omega

why are you talking about v

There is another way to express centripetal acceleration that uses the angular velocity. It's advantage in this case is that all parts of the victim have the same angular velocity.

angular momentum = rotational inertia * rotational velocity is the equation given, but i'm not told in my book how to find rotational inertia, and rotational velocity requires a time frame which is not given.

why would you need inertia?

i have no idea.

why would you need momentum?

@heather Blue gave you the equation

$a_c = \omega^2 r$?

You know $a_c$ and $r$

the whole point with this stuff is that $\omega$ is the same anywhere

@heather what book?

"Conceptual Physics" by Paul Halmos

::spins in chair::

Oh, I have his Measure Theory book

er, wait, wrong name

Paul Hewitt

@Blue Measure Theory is worthy of capitalization

@Blue what?

I watched that movie years ago

my working memory is about 18 months

Ultron?

That's years old

2015

April 2015

The only sentence it has is

That's >24 months

I recall nothing about it

> Centrifugal acceleration is directly proportional to the radial difference from the hub

in the chapter.

what the hell is a hub @heather

like the hub of a wheel - the outer rim.

it follows easily from vector calculus in polar coordinates

okay

@heather do you at least know that $v_1/r_1=v_2/r_2$?

::blinks::

@heather maybe read amazon.com/…

it should explain this

@Blue if you're going to be a mathematical physicist at least use $\wedge$ instead of $\times$

@Blue I thought you said it was $ = \omega^2/r$...

nvm, it's horrible

should i watch the video or listen to you?

get Giancoli

giancoli?

the famous physics book

Physics: Principles with applications?

(says google)

no, for physicists and engineers

okay

i'll see if i can find it

damn Feynman lectures

my dad has a copy of those, i've read some of them.

my reading list grows exponentially each time i talk about physics in here =P

okay.

@heather do you want a math reading list

I gave one to @Blue

sure

I think he ignored it

probably a smart decision

@Blue If you're interested in the things I am, I like to think I have very good taste in books.

@Blue 2 years?

@Blue I think I knew more math than you when I was in 3rd year of HS

But "level" isn't a good thing to measure

You're never going to know all that I know, and vice-versa