The h Bar

John Rennie

5:00 AM

@KaumudiHarikumar Yes. But this is just because of the specific mechanism by which a lake cools.

user228700

@JohnRennie What do u mean?

John Rennie

In some hypothetical situation where the liquid was being cooled at its base the behaviour would be different.

user228700

Yes, OK.

John Rennie

But I can't think of any situation in nature where this happens.

Obviously you could do it in the lab.

user218912

@0celo7 tex.stackexchange.com/questions/53698/…

user228700

5:02 AM

See, this is why I need your expert help. None of the sites that Google led me to made this distinction between actually freezing and freezing and then sinking.

Mew

why would it freeze then sink

this would only happen in a lake, and lake is made of water where the solid is LESS dense

if the material isn't water, there is no reason to believe the cooling occurs at the top

0celo7

@IceLord kewl

user228700

I was very confused. Thanks a ton sir! :-) Are you unwell? Or is it OK if I come back and ask more doubts(maybe) like yesterday?

John Rennie

I'm OK :-)

0celo7

projecteuclid.org/download/pdf_1/euclid.jdg/1214433166

nice!

John Rennie

5:04 AM

i had a drink or two last night, but I'm fine now - mostly :-)

user218912

@JohnRennie I still need help is that okay?

John Rennie

So if you have any more questions please ask.

@IceLord let me scroll up and look at your question ...

user218912

so for my expectation value of the position operator for coherent states

user218912

I get $z\mathrm{cos}\omega t$

user228700

@JohnRennie OK sir, thanks a ton! (If I actually make it into one of the colleges I do want to get into next year, you definitely get some of the credit!)

user218912

5:05 AM

but it's supposed to be $Az\mathrm{cos}\omega t$

user228700

I will ask, thank you :-)

John Rennie

@IceLord I'm afraid I don't know anything about the Heisenberg approach in QM. Sorry :-(

user218912

where $A = \sqrt{\frac{2}{m\omega}}$

user218912

it actually has nothing to do with heisenberg's approach (except that we're using it)

user218912

it's just a basic harmonic oscillator problem

user218912

5:06 AM

it's a math error

Mew

Position operators that change with time IS part of the Heisenberg picture

user218912

I know

Mew

Show me your working from A to Z and I'll point your error if you don't see it first

But surely you will see which line doesn't follow logically from the line before it

user218912

all my math is correct

user218912

because it agrees with the general result

Mew

5:08 AM

if you are 100% sure of this, then what is the probleM?

user218912

problem is

user218912

there is a factor in front of the answer in my problem set.

Mew

Sometimes the answers in problem sets are wrong

user218912

maybe

user218912

@0celo7 do you have any input?

0celo7

5:12 AM

@IceLord you tricked me.

you said this didn't have to do with homework

I'm not talking to you any more

user218912

what?

user218912

my problem from before was not homework.

0celo7

I don't believe you.

Mew

Ocelo I have a question

not homework

user218912

@0celo7 wait why is it bad if it's homework?

Mew

5:16 AM

@IceLord cos it makes ppl lazy

0celo7

I said I won't help with homework

@Mew Yes?

user218912

@0celo7 why?

Mew

it's like feeding animals, they once you start they become dependent and forget how to hunt

user218912

that's true but I'm doing most of the work myself

user218912

I just get stuck on some steps

0celo7

5:16 AM

@IceLord I don't remember, but I have it written in my notes.

user218912

@0celo7 xD

user218912

is it because I said I take your help for granted like 5-7 months ago?

Mew

@0celo7, how can we form memories through time if entropy is always increasing

shouldn't we be forming our memories backwards in time instead?

0celo7

I'm not a physicist

@IceLord yes

user218912

I didn't mean that!!!

user218912

5:18 AM

cmon man

user218912

i'm sorry :(

0celo7

Sorry, I'm a geometer

dunno any QFT

user218912

this isn't QFT yet

0celo7

or QM

user218912

you're in a QM class...

0celo7

5:19 AM

Proof?

Got to work on balls a bit, cya

user218912

@0celo7

user218912

Aug 29 at 2:24, by 0celo7

I'm taking QM right now

0celo7

wrong 0celo7

user218912

if I click the name it links to your profile.

0celo7

weird.

user218912

5:22 AM

there's only 1 0celo7 though, if you search on stackexchange physics or math for users named 0celo7 only you show up.

user116211

@IceLord Maybe it was his doppleganger from Earth 2 ;P

user218912

perhaps

0celo7

@IceLord I have MPD.

Sometimes I'm not myself.

user218912

you also said you have toxoplasmosis.

user218912

what if one of your personalities thinks it has toxoplasmosis but you really don't in your other personalities?

0celo7

5:25 AM

I don't remember that, so it's reasonable.

user116211

Dude, maybe some of your personalities does QM....

user218912

tell to be fair your personality since march 2015 has changed a lot @0celo7

0celo7

@IceLord Oh?

How so

user218912

you're like a completely different person now.

user218912

i blame math.

0celo7

5:28 AM

Like what?

user218912

idk if I can explain it.

0celo7

do it

user218912

tomorrow

user218912

gonna sleep now

user218912

bai

0celo7

5:30 AM

bye

user116211

@IceLord o/

user116211

Man, you crazy... why would one use \large in \displaystyle;( Are you blind? damn...

0celo7

what?

user116211

There came a post today where OP didn't use MathJax; I edited that into $${H = \sum_{0}^{N}\left[ − V_1(|g_n\rangle \langle g_{n+1}| + |g_{n+1}\rangle \langle g_n|) − V_2(|g_n\rangle \langle g_{n+2}| + |g_{n+2}\rangle \langle
g_n|)\right]}\,.$$

user116211

5:45 AM

Another came and made this into this: $$\large{{H = \sum_{0}^{N}\left[ − V_1(|g_n\rangle \langle g_{n+1}| + |g_{n+1}\rangle \langle g_n|) − V_2(|g_n\rangle \langle g_{n+2}| + |g_{n+2}\rangle \langle
g_n|)\right]}}$$

John Rennie

Chrome looks different this morning (unless I'm more hungover than I think). Has there just been a Chrome update released?

0celo7

why would you be hungover?

John Rennie

And some drunken oaf spilled crisps (potato chips) on my floor last night then trod on them.

I must have been visited by a crisp eating burglar who forgot to steal anything.

user116211

@JohnRennie Is the auto-update enabled?

John Rennie

@MAFIA36790 yes. I generally just let Chrome update itself whenever it wants.

Aha googlechromereleases.blogspot.co.uk/2016/09/…

user116211

5:54 AM

75

Q: How can I check the version of Google Chrome without it upgrading itself without asking me?

The version of Google Chrome can be checked by going to chrome://help. However, if Google Chrome is not up to date, it will upgrade itself without asking the user. How can I check the version of Google Chrome without it upgrading itself without asking me? I use Google Chrome on Windows 7 SP1 x...

user116211

@JohnRennie Must be your neighbor who likes pranks.

John Rennie

:-)

user116211

Hey @JohnRennie, I was thinking of making some congratulatory post at meta when you reach 200k like they did at maths; you wouldn't mind; would you?

user116211

Or maybe should I wait for 500k ;))

John Rennie

6:04 AM

It's getting close :-)

I'm not sure I would make a meta post. if you looked in detail at those votes I suspect you'd find that half had come from basically simple answers that just happened to get on the hot network questions list.

Secret

@0celo7 It would be cool if botany really had something to do with it

John Rennie

Although I confess I feel pleased about (almost) reaching the 200,000 mark it's mainly a result of answering so many questions rather than a sign of great genius.

user116211

@JohnRennie hmm, a humble nerd ;P

John Rennie

Sadly I can't claim to be humble - anyone who knows me would be happy to confirm that :-)

user116211

I really want to have such post like those in Maths here also and you are the first here to reach 200k, irrespective of whether the posts had simple contents or not.

John Rennie

6:08 AM

It's just the way the rep system works

user116211

I would ask @DavidZ if it would be okay to do so.

John Rennie

If you want to post something then that's fine by me, but I'd focus on why this makes the site a success i.e. it shows a high level of activity.

user116211

@JohnRennie sure :)

user228700

@JohnRennie Almost congratulations sir! When did u join the site?

user116211

It was a common practice there at Maths @JohnRennie, but recently it has been called off; you know for there are many users who cross these landmarks there....

John Rennie

6:11 AM

@KaumudiHarikumar Five years eight months ago according to my profile

user116211

And nothing is uncommon there now to cross the landmark but here it is for the very first time!!

user228700

@JohnRennie Whoa.

user228700

I discovered this website only recently. It's very sad that more people(here) don't know about it.

user116211

@KaumudiHarikumar I frequently read the posts here back at std. IX; no matter what you google, you would get at least one post of Physics SE ;))

John Rennie

@KaumudiHarikumar It has really improved my knowledge of physics. If you look at some of my early answers they are embarrassingly naive. Answering questions forced me to relearn all the physics I'd forgotten over the years. As well as learning lots of new physics.

user228700

6:15 AM

Actually, on second thoughts, I think it's actually better for experts like @JohnRennie that more people here aren't aware-you'd be bormbarded with LOADS of questions every day :P

user116211

@KaumudiHarikumar Homework questions; I'm sick of that ;((

Xasel

Hey everybody

user116211

Most queries from our country comes as blunt Homework..... they think it's a forum which is totally wrong.

user228700

@JohnRennie :-) I see. It's a wonderful website. I've embarked on a horribly long and tiring quest, so to speak. I didn't join college this year just so I can try again, when the entrance exams come around again, next year. I haven't got any study partners/teachers around and posting questions here/this chat has helped me more than anything else. I'm really glad that I found this website :)

user228700

@MAFIA36790 Yeah, that's true and it sucks :/

Xasel

6:18 AM

@MAFIA36790 : Not if they are from text like Dave Morin :P

^I mean those *** star ones

user116211

@Xasel I guess not ;P

user116211

Most are from test materials....

user228700

And it's kind of amazing that this website caters to specific doubts in concepts rather than doubts. It's almost exactly what I need right now :D

user116211

I'm checking what your first answer to my query was @JohnRennie ....

Xasel

well may i ask a ahomework problem if you guys don't take offense

user228700

6:20 AM

@Xasel xD

John Rennie

@Xasel you can ask anything in the chat.

But of course we don't have to answer :-)

Xasel

@JohnRennie : EVerybody in HS has studies the formula for electron energy absorption /release

0celo7

@JohnRennie don't say that.

@Xasel Really?

I'm in a QM class and I've never heard of that

Xasel

He is pulling my legs with spring consta of infinity

in bohr model I mean

user116211

Here it is @JohnRennie:

user116211

6:22 AM

4

A: How can there be really any instantaneous velocity?

bright magus puts his finger on the problem when he says in a comment: There is no movement without time flow. Physicists describe the universe as a four dimensional manifold, in which points are identified by their position $(t, x, y, z)$. The time coordinate $t$ is just a coordinate like $x$, ...

John Rennie

Ah, I remember bright magus. There was a chap convinced that his own personal interpretation of GR was correct and everyone else was wrong.

Xasel

well then we can equate it to find out it to find ut the photon electron will absorb/release when transtiong from one orbit to another

but does the frequency of photon should be exactly same as calculated one

since according bohr model

electron are whizzing very fast

and I guess there shou;d be doppler effect?

0celo7

> Physicists describe the universe as a four dimensional manifold, in which points are identified by their position $(t,x,y,z)$

>:(

pls tell me you understand what's wrong with that now

user116211

@0celo7 Should I dig out the yesterday's quote you gave? Lanczos too said that....

John Rennie

@Xasel: are you thinking that because the electron is moving fast the light emitted by it should be Doppler shifted when it reaches us?

0celo7

6:25 AM

@MAFIA36790 >>>>:((((((((((

Xasel

nah i mean say we fire a photon to excite the electron to next orbit

Then does the frequency of photon

John Rennie

@0celo7 that looks fine to me. What's wrong with it?

Xasel

should be same as calculated one from formu

user116211

@0celo7 What? I believe you.

Xasel

or we have to account for doppler shift?

John Rennie

6:26 AM

@Xasel The simple answer is that the Bohr model is wrong so we shouldn't worry too much about fine details like this.

0celo7

@JohnRennie a) charts are not unique b) a chart needn't cover all of spacetime

John Rennie

The more complicated answer is to say that the Bohr model contains no explanation of how the transitions between levels occur.

0celo7

You do not "identify" a point with its coordinate.

John Rennie

So when the photon comes in there's no explanation of how exactly it is absorbed and whether a Dopplershoift would occur.

Xasel

hmm..what happen in QM then.How QM treats my question?

John Rennie

6:28 AM

In QM the electron isn't whizzing around the atom.

Xasel

enlightne me more then what happens on orbital level?

John Rennie

In the presence of light the ground state isn't an eigenfunction of the Hamiltonian so it changes with time. If we study the time dependence we find the initial state evolves into a mixed state.

The mixed state is a mixture of the ground state and the excited state.

So when we measure the state there is a non-zero probability we find it in the excited state.

The photon isn't absorbed in any simple way. The atom and photon together form a mixed state that can evolve into a state where there is no photon and the electron is in the excited state.

0celo7

@MAFIA36790 I misunderstood.

John Rennie

I have to go offline for a bit to check my servers. Back in an hour or so.

Xasel

lost it(due to lack of my math backgorunf :( )

user116211

6:33 AM

@Xasel Which one didn't you get?

Xasel

I don't know what's HAMiltonian and eigenfunction part

user116211

@Xasel Well, wait....

Xasel

....for myself to develop rigorous mathematical backgroung

:(

Anyway thanx John

user116211

@Xasel Hamiltonian is the infinitesimal time-translation generator.

user116211

@Xasel As that of eigenfunction, you can find it in any introductory linear algebra book.

Xasel

6:38 AM

You know that:I am grateful that you are trying to make me understand the concept..but thing went a bouncer due to lack of my background

user116211

hmm.

John Rennie

@Xasel: while I'm (briefly) back - I'm afraid you'll need to learn some basic quantum mechanics to understand what is going on. I don't think there's a simple explanation like the Bohr model that isn't misleading.

user116211

@Xasel See if you get this informal introduction to Hamiltonian:

user116211

8

A: What is $\langle \phi | H | \psi \rangle$ in QM?

This is a supplement to freude's correct answer: Hamiltonian is the infinitesimal generator of time translation defined as $$\mathrm{\hat{U}}(\mathrm dt)= 1- \frac{i}{\hbar} \mathrm{\hat{H}}(t)~\mathrm dt\;.$$ Time-Evolution Operator: Let the system be at $|\phi\rangle\;.$ Now, let's wait ...

Xasel

@JohnRennie : I know that ...that's why I disn't proceed much..just jot it down ...If only I have luxury of quality time

@MAFIA36790:Thank you

user116211

6:45 AM

@Xasel Mind you, this is not a rigorous post; to get the actual things, you have to read some QM treatise.

user228700

Hey, um, I keep coming across the term "total heat capacity" and googling is not helping. Anybody know anything?

user116211

@yuggib: o/

user228700

The word to be emphasized is total.

user228700

Never mind.

user228700

I think I understand. My textbook is weird :/

user116211

7:04 AM

WoW! Kyle changed his profile pic:

user116211

Kyle Kanos, South Carolina, USA

18.7k 10 37 73

homework-and-exercises fluid-dynamics astrophysics newtonian-mechanics quantum-mechanics thermodynamics electromagnetism

user116211

Seems to me of the old Transformers animated show.

Xasel

hmm..what so great about it?

user116211

@Xasel That he still comes here and had time to change his profile bio as well as his pic.

Xasel

@KaumudiHarikumar:which textbook you are using?

Danu

7:12 AM

@0celo7 Why would I? The pdfs are texed---the style is not 100% the same as mine but I customize my documents to look very similar.

jyotishraj thoudam

Is there someone here who can discuss some problems in quantum mechanics with

Danu

Just pose your question @jyotishrajthoudam, instead of asking to ask

jyotishraj thoudam

0

Q: Double Slit Experiment/Transition of Classical to Quantum problems in Probability Addition in "An Experiment on bullets"

The First Picture is taken out from the Book The Character of Physical Law By Richard Feynman And the second picture is from his own The Feynman Lectures on Physics. Both figures correspond to the An experiment with bullets topic which appear on his lecture. In the first lecture $N_1$ , $N...

quantum-mechanics classical-mechanics double-slit-experiment probability interference

Here

user116211

@jyotishrajthoudam A popular thought experiment of Feynman, if that is what you are talking about....

jyotishraj thoudam

yes

user228700

7:15 AM

@Xasel It's one of them coaching textbooks. Guess it's bound to be weird.

jyotishraj thoudam

Will appreciate if you'd help me understand

user116211

@jyotishrajthoudam What's the thing in the experiment that bothered you?

user228700

Anyway, I've got another doubt. Thought I'd post a question but it's really small so figured I'd ask here instead.

jyotishraj thoudam

The problem where I don't see how the probabilities adds up and its equal to the probability when both holes a re open

user228700

It was my understanding that the heat capacity of a substance is defined as "The amount of heat to be supplied to a system to raise its temperature by $1°C$"

It was only recently that I realized that this property of a substance is actually a *path* function, meaning that it assumes different values for different thermodynamical processes that the system undergoes. Is this property *defined* in this way, so that it changes for different processes?

user116211

7:18 AM

@jyotishrajthoudam Wait, let me read your post, first...

user228700

If so, I think it's ludicrous that they define it as being "The amount of heat required to..." in all the textbooks! That, or maybe I'm enough of an idiot to not have understood properly.

jyotishraj thoudam

yes thank you, I tried to demonstrate an example of my confusion, and some issues with the graph I found on both of his books @MAFIA36790

user116211

@KaumudiHarikumar Common abuse of the terms; I always used thermal energy as this is the term used by the standard text; heat is the process, thermal energy is the energy.

jyotishraj thoudam

So, Is my question Understandable @MAFIA36790

user116211

@jyotishrajthoudam Did you get the word lumpiness Feynman used frequently?

jyotishraj thoudam

7:32 AM

Lumpiness meaning bullets are received as a whole not as broken pieces? @MAFIA36790

user116211

@jyotishrajthoudam yes, that means what? A single bullet would go through either of the slits.

jyotishraj thoudam

yes I understood @MAFIA36790

user116211

So, the events of going either through slit one or two is disjoint or mutually exclusive.

user228700

@MAFIA36790 That doesn't exactly answer my question...

user116211

@KaumudiHarikumar I didn't answer any of your question....

user116211

7:35 AM

@jyotishraj, So, by the addition theorem of probability for two disjoint events,

user228700

@MAFIA36790 Then what did you do :?

user116211

$$P_{12}= P_1 + P_2\,.$$

user116211

@KaumudiHarikumar I just marked that you were right the statement is ludicrous.

jyotishraj thoudam

@MAFIA36790 I know that but here in this experiment I pointed out that event though both are independent events I don't think how it adds

user228700

@MAFIA36790 Right, OK :P

jyotishraj thoudam

7:37 AM

@MAFIA36790 I don't know how it adds

user116211

@jyotishrajthoudam A side-note, independent need not mean disjoint or mutually exclusive.

jyotishraj thoudam

@MAFIA36790 Feynman also pointed out that we cannot receive two bullets at the same time. Yes, mutually exclusive sorry

user116211

Pribably @jyotishraj, you have to wait for I'm going back to my studies and need to complete writing some posts first; wait for some others to enlighten you....

jyotishraj thoudam

But my point was that when one of the hole was closed and if through the other hole 10 bullets has passed through then we can also say that under that hour as the gun was firing at a constant rate in all direction, the same no. of bullets will have been blocked

@MAFIA36790

OK@MAFIA36790\

John Rennie

@jyotishrajthoudam I'm working at the moment. Sorry :-(

jyotishraj thoudam

7:44 AM

oK, pLEASE do reply when you're free @JohnRennie

user116211

7:59 AM

BTW, @jyotish, did you notice that the gun in the experiment is not good, and fires randomly over a wide angular spread?

Secret

But how do they took care of the interference between overlapping wifi signals?

user116211

I didn't see the word constant in any of his lectures on the experiment.

user116211

Anyways, back to my work

David Z

8:15 AM

@MAFIA36790 you mean congratulatory meta posts? I'm personally opposed to them but it's up to the community. As with anything else, you can make the post and see what happens. (I guess check to see if there is any precedent first)

user116211

@DavidZ sure; currently the practice has been called off at Meta Maths and there was a separate post that asserted to stop the practice there; but we know reaching the 100k or 200k landmark has become common there; that may be justified why they called of thus. But here at Physics SE, it is for the very first time. Of course, I would be glad to do this if the community gives their accord.

jyotishraj thoudam

@MAFIA36790 Yes

@MAFIA36790 But Feynman also assumes it is firing at the same rate

David Z

8:53 AM

@MAFIA36790 The only way to find out if the community agrees is to just make the post and see what happens. Or I guess you could make a meta post asking if you can create congratulatory meta posts, but that's starting to get a bit silly :-P

FrancescoS

Hi guys. A question in general relativity. I work with Rindler metric $ds^2 = e^{2a\xi}(-d\tau^2 + d\xi^2)$. I choose an observer at fixed $xi$ and ask my self what is is velocity in the coordinates $\tau,\xi$ i.e. $(u^\tau,u^xi)$. I would say $u^tau = e^{-a\xi}$ and $u^\xi=0$. Do you think is it correct?

user116211

@DavidZ nice idea; thanks.

CodeRatchet

9:17 AM

Good Evening / Morning All,

I'm currently studying physics so please bare with me, I've been working through a physics paper which consists of 20 questions. Which range from easy to hard, I'm struggling to answer the remaining four question and I'm hopeful someone could give me a hand, the questions are as follows:

1) An adjustable cylinder containing oxygen is stored at room temperature at your clinical practice. One of your colleagues accidentally depresses the lever that controls the cylinder size. As a result, the cylinder has reduced to half its size. Explain how this incident will …

John Rennie

@KaumudiHarikumar: re the specific heat - for solids and liquids the definition of specific heat is fine because all the energy you put in goes into increasing the temperature.

It's only for gases where some of the energy you put in goes as work instead of raising the temperature.

Even then it's still a good definition for $C_v$.

@CodeRatchet we're generally not keen on just giving answers to homework. However if you want to say how you think you should be approaching the problems we'll be willing to help.

CodeRatchet

@JohnRennie Hey John, thanks for the response, That's just it I'm not sure how to approach these questions. :(

John Rennie

@CodeRatchet well start with question 1. Do you know what law relates the pressure of a gas to its volume?

CodeRatchet

Pressure is measured in pascals if I remember correctly

@JohnRennie ^

John Rennie

That isn't an answer, now is it? :-)
Have you tried Googling "gas pressure volume" or something similar?

CodeRatchet

9:32 AM

Just goggled what you suggested

John Rennie

And ...

CodeRatchet

Boyles ?

John Rennie

OK, now look on Wikipedia to see what Boyle's law tells you.

user228700

@JohnRennie Right, OK.

user116211

Hey @JohnRennie, would you mind shed some light in this:

user116211

9:42 AM

0

Q: Why does the line-element $ \bar{\mathrm ds}^2 =\sum_{i, \, k= 1}^n g_{ik}~\mathrm dx_i\mathrm dx_k$ not preserve the Euclidean Structure?

I was reading Kinetic Energy and Riemannian Geometry in The Variational Principles of Mechanics by Cornelius Lanczos; here is the concerned excerpt: Let us define the line-element of a $3N$- dimensional space by the equation: $$\overline{\mathrm ds}^2 = \sum_{i\,=\,1}^Nm_i~(\mathrm dx_i^2 + \...

riemannian-geometry classical-mechanics

user116211

I'm currently reading different topic hoping to get a response on this; would appreciate if you mind say something on this.

user228700

@JohnRennie BTW, I JUST finished Thermo. in Physics and now I'm doing the same thing in Chem. and I couldn't explain to you how frustrating and confusing it is, even if I tried :-(

John Rennie

@KaumudiHarikumar in my first year at university I learned thermodynamics in (1) the physics course, (2) the chemistry course and (3) the crystallography course, and they all approached thermodynamics differently!

@MAFIA36790: are you asking how a flat space can appear curved just due to a change of coordinates?

user228700

@JohnRennie Oh God, three different ways?! Must've been one hell of a year for you :P

CodeRatchet

@JohnRennie Ok so I think the answer to number 1 would be "As the cylinder has decreased in size the pressure of the gas will increase, the volume of the gas will become more dense" ?

John Rennie

9:46 AM

@KaumudiHarikumar to be fair, when you put it all together you had learned a lot of thermodynamics!

@CodeRatchet yes, that seems a pretty good summary to me. I assume the questions aren't looking for precise answers i.e. exactly how the pressure changes? I take it this is an introductory course?

@CodeRatchet Although the statement the volume of the gas will become more dense doesn't make sense. I would just say the gas will become more dense.

user228700

@JohnRennie Yeah. No pain, no gain eh?

John Rennie

@KaumudiHarikumar Chemists are mostly interested in enthalpy, free energy and chemical potential, and aren't that fussed about ideal gases. So it's natural they have a different emphasis to physics.

@MAFIA36790: ping, ping ...

CodeRatchet

@JohnRennie Sounds good to me thanks, I will expand this answer later but for now I'm just looking to get a brief answer. That's correct it is an introductory course.

John Rennie

@0celo7: shouldn't you be tucked up in bed by now? :-)

CodeRatchet

@JohnRennie Number 2 would that fall into Energy Transfer?

John Rennie

9:50 AM

@CodeRatchet OK. Now take Q4 because that's the easiest of the ones left.

user116211

@JohnRennie No, I know that. Lanczos mentions that the Euclidean structure is not preserved not due to the mere transformation to the generalised curvilinear coordinates in the second case.

CodeRatchet

ok

Number 4

user228700

@JohnRennie Yes, but I wonder why they had to invent a whole new sign convention! WHY?!

user116211

@JohnRennie I was about to go to lunch... ;P

user116211

@JohnRennie I'm seeing it often these days that 0celo comes at the dead night here ;))

John Rennie

9:52 AM

@CodeRatchet There is a well known effect of motion on sound. The xxxxxx effect. Does this ring any bells?

( the "xxxxxx" is a placeholder for the actual name)

CodeRatchet

@JohnRennie Doppler ?

John Rennie

@CodeRatchet Bingo!! :-)

CodeRatchet

@JohnRennie Ok let me go put together a good example

John Rennie

Have a quick read of the Wikipedia article on the Doppler effect and see if it answers Q4.

user228700

@JohnRennie My Chem. textbook is kind of crappy, and I can't seem to find great vids :-(

John Rennie

9:55 AM

@MAFIA36790 we can get back to this later - after lunch. I'll be around later today. I'm still not sure I un derstand what you're asking though.

@KaumudiHarikumar thermodynamics is normally dealt with in physical chemistry, as opposed to organic or inorganic chemistry, and the standard works are the books by Atkins and Moore.

The Atkins book is easier to understand while the moore book is more thorough.

user228700

@JohnRennie What do u mean more?

John Rennie

@KaumudiHarikumar Moore not "more"!

books.google.co.uk/books/about/…

The Atkins book is:

amazon.co.uk/Atkins-Physical-Chemistry-Peter/dp/0199543372

user228700

Thorough! You meant more thorough. OK :P

John Rennie

That's what I said ...

2 mins ago, by John Rennie

The Atkins book is easier to understand while the moore book is more thorough.

user228700

Yeah, misread thorough as though, sorry.

John Rennie

9:59 AM

:-)

user228700

How big is it..?

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