The h Bar

4:54 AM

Dammit! BBC Radio 1 have a rock/metal show on Sunday and listening to it is an essential part of my Monday morning.

But this weekend there have been special programmes about Ibiza all weekend so instead of three hours of rock/metal we get dance music from Café Mambo!

Now how am I supposed to wake up?

5:09 AM

OK it's going to have to be three hours of Industrial, Darkwave, EBM, Post Punk & Gothic. Oh well :-)

Qmechanic

8:56 AM

FYI: July 27, 2017: general-physics tag now officially burninated & blacklisted. August 4, 2017: physics-careers tag now officially burninated & blacklisted.

3

The Raiders of Las Vegas

Burninate

10:35 AM

Hi @Avantgarde

Lol hi, @Balarka were you waiting for me to appear?

Kinda

I found an album today

Sure?

which one

I searched for dark, progressive albums and after an hour of interneting I found Peter Gabriel's 1980 album.

I have listened to the first three tracks till now but I am getting blown away by it

It's old so maybe you already know it

Peter Gabriel released a dark progressive album?

10:38 AM

Actually no, I haven't heard practically anything by Gabriel

Apparently. The album is called... "Peter Gabriel"

This one?

yeah

I wouldn't have said that was dark and progressive ...

There were quite a few hit singles from it.

Well, uh, I don't know what classifies as dark. I think it's exactly what I was looking for.

The first two tracks are pretty scary, I would say :P

user228700

10:42 AM

Hey, everyone! :-)

user228700

@JohnR: Are you around?

@Kaumudi.H Morning/Afternoon

user228700

Afternoon :-) Just got back from college; doing laundry.

user228700

Will you be free tonight, then?

Yes, what time i.e. what time in Kochi?

user228700

10:44 AM

9 PM, didn't you say?

Interesting, @Balarka. I can say I wouldn't know something quite similar to that. Genesis is an obvious option, however.

@Kaumudi.H 9 p.m. your time is 16:30 here, which is fine. It could be a bit earlier if you want, though IIRC you have dinner at 20:00 so I guess earlier isn't great for you.

user228700

No, no, it can definitely be earlier than that!

user228700

What time, then?

Ping me here when you've finished dinner. I don't have any commitments today so my plan is to go for a walk in the early afternoon. I should be back from about 15:30 BST thugh it could be as late as 16:00.

10:47 AM

@Avantgarde Yeah I'm super liking this. I haven't heard anything by Genesis.

@Kaumudi.H Or I'll be around here for another hour or so...

Bits of it is reminding me of 1.Outside (you might try that if you haven't already).

user228700

@JohnRennie Wokay, I'll ping you then.

See you later then ...

user228700

@JohnRennie I've decided to look at it first myself and then ask you about it later.

10:48 AM

@Kaumudi.H Any advance warning on what you want to ask about?

Just so I know what to revise :-)

user228700

Haha :-) Unfortunately, no, I've got so much on my plate that I dunno where to start. It's kids stuff for you, I'm sure :-)

user228700

How has your day been?

Ok, we'll just see how it goes.

user228700

Yep. Shouldn't we create a room?

Incidentally, if any of the other students want to join in that would be fine.

@Kaumudi.H do you want to create a room or shall I?

user228700

10:50 AM

Hehe, none of my friends are on S.E. If they do have questions, I'll show them a bookmarked conversation or something. Gosh, I keep on forgetting just how kind you're being!

none of my friends are on S.E. - that can be fixed of course :-)

user228700

@JohnRennie You can do it :-)

what to call it ...

user228700

@JohnRennie Ah, but I don't think that any of them have started taking revision seriously yet; they're always hanging around in the hallways...

user228700

I have made one friend who's a bit like me so if he asks, I'll be sure to let him know :-) THANKS SO MUCH.

user228700

10:52 AM

@JohnRennie You're the pun master, you name it! :-)

I can't remember how you create a room ...

user228700

Hang on, I'll do it.

user228700

Tell me what to call it :-P

In at the deep end

user228700

Nice!

user228700

10:55 AM

:-) I'll come back and ping you later, then.

user228700

But:

user228700

6 mins ago, by Kaumudi. H

How has your day been?

@Kaumudi.H Can you make me a room owner?

user228700

I dunno, hang on.

user228700

Done!

10:56 AM

@BalarkaSen Outside?

The Power!!! :-)

user228700

@JohnR: MISTAKE IN MESSAGE, EDIT IT :-P Just in case you start shouting at me for not warning you earlier :-P

David Bowie - 1 Outside (Full Album)

@Avantgarde This shitz:

►

My fav album of all time no question

@Kaumudi.H Huh?

user228700

Dang.

user228700

10:58 AM

You said "Cool, I'll wait for you ping".

Ah, oh well :-)

@BalarkaSen Ah good old Bowie

user228700

:-)

user228700

And what's for lunch?

As for my day ...

10:58 AM

@Avantgarde Have you listened to that album?

user228700

WHAT ARE THEY?! They look great!

It's a type of bread called brioche that I've used to make sort of bread rolls.

@BalarkaSen No. I just put it on. But I'll get to it sometime later more seriously with earphones on

The filling is ham and cheese.

user228700

10:59 AM

Ah, nice.

With Jamaican jerk seasoning.

It does sound good from the beginning indeed

user228700

All I've had all day are two dosas :-(

user228700

I must try to take better care of my stomach...

@Avantgarde Make it your priority album. I can't even explain how good it is.

:p

this one's another Bowie-Eno collaboration by the way

11:00 AM

@Kaumudi.H Take care of your stomach and it will take care of you! (a meaningless statement but it sounds good :-)

user228700

Hehehe :-)

user228700

OK, I must run now. @JohnR: I'll ping you later tonight! Have a great afternoon!

Bye

@BalarkaSen Oh okay. Will get to it

Secret

11:35 AM

cnet.com/news/…

We Australia have nothing that doesnt try and kill you

CooperCape

that just made me itchy :(

12:20 PM

What's going on

12:39 PM

Hello! How is it going?

I am new in physics, so maybe the question is stupid. If a light is a wave and electron also has wave properties, could adsorption of light by electron in atom be considered as constructive interference of this two waves?

Than it is clear why only light of certain wave length is adsorbed.

I would say no

Where I am wrong than?

Because the matter wave associated with the electron is not the same that an electromagnetic wave (the photon)

Oh, indeed.

I missed this point

@JohnRennie My paranoia got the better of me and I reapplied the thermal paste

12:50 PM

In fact the interpretation of the matter wave it's sort open to discussion

I see.

I only started to learn the physics.

Than one more thing.

On college?

Or independently

@БеляковаАнастасия It is highly advisable to choose a name in Latin letters.

No, now by myself, just for self development.

Cool

12:53 PM

@DavidLeonardoRamos Thanks.

Np

So, the other thing is: photons have mass=0, do they?

Yes

But at the same time e=m*c^2, is it?

No rest mass

No

Q: How do electrons and photons interact?

12:55 PM

But when m=0, e=0? Rest mass? What does it mean?

Secret

Question requires quite high level of treatment

3

Two electrons, or an electron and a proton, interact with each other because of the Coulomb potential, which can also be seen in the Schrödinger equation (which is the equation that describes the motion for elementary particles). But how do an electron and a photon interact? Why can a photon kic...

@БеляковаАнастасия no

where I am wrong here?

@Secret Thank you.

e=mc^2 only holds for particles with mass because that m is the rest mass

@БеляковаАнастасия See physics.stackexchange.com/q/143652/50583 and physics.stackexchange.com/q/2229/50583

Secret

12:56 PM

As for a semiclassical treatment, : astro.uwo.ca/~jlandstr/p467/lec3-emradiat

for a photon it would be e=p*c

and p here is what?

@БеляковаАнастасия The momentum of the photon. Note that $p = mv$ is not a suitable definition of momentum in the relativistic case.

@ACuriousMind Thanks!

@Secret Thanks!

@ACuriousMind Than how is it defined here?

BTW, what units are used in e=mc^2?

Q: Is the concept of rest mass correct?

1

Is the concept of rest mass correct? All these years, we (me, and my classmates of Undergraduate 1st Year) have been accustomed to the concept of rest-mass, and the relativistic transformation of mass at speeds of the order of c. We had been introduced to this concept during our school-years, we...

special-relativity mass

Some random discussion about the concept

1:00 PM

@DavidLeonardoRamos Cool, thanks!

@ACuriousMind this is the best I can do

hahaha

@DavidLeonardoRamos I think our canonical discussion of invariant mass vs. relativistic mass is physics.stackexchange.com/q/133376/50583

@0celóñe7 Did you have to pin him in place there? oO

@0celóñe7 :)

@ACuriousMind Yes

he doesn't like the fans

1:02 PM

@ACuriousMind Oh nice

Which book in physics you read you find the best?

@БеляковаАнастасия "An Introduction to the Regularity Theory for Elliptic Systems, Harmonic Maps, and Minimal Graphs" by Giaquinta and Martinazzi

@0celóñe7 great. thanks.

Pranav

2:06 PM

any1 there??

guys consider this question

"Give a situation in which the force of static friction acting on an object is infinite"

isnt this question wrong?/

static friction can no exceed a max value(limiting friction)

*not

if the limiting friction is infinite

only two things can happen

either N is infinite or mu (k) is infinite

this means either the weight of the object(if its kept on level ground) is infinite

which just cant be right?

or we can say that an external agent is applying an infinite force on the object from above

again an infinite force isnt possible

and last mu (k) cant be infinite

since the questions says "a situation" it wants us to give a real life situation, and thus in real life none of the above 3 things can be infintie

right??

my physics teacher said the answer to this question is -

"when an object is rolling on a surface, some deformation takes place between the surfaces. thus rolling friction acts on the object, and we can say in a way that the amount of static friction acting on it is infinte

"

isnt this just plain wrong

if the type of friction itself changes then how can we say anything about static friction?

and in any case even if rolling friction is some type of subpart of static friction , it just cant be infinite

pls help me here

2:25 PM

@Pranav It's one (admittedly strange) way to define the approximation of "pure rolling" - when static fricton is infinite, then no amount of force will lead to the object sliding across the surface, i.e. it can only roll across it.

Of course you are correct that in real life there are no infinite forces, i.e. at some point when you increase the force applied to a wheel it will start slipping.

Anonymous

2:47 PM

@Avantgarde I spoke with him today. He told me to decide upon a few ideas for the project. It should be such that it has industry relevance so that it can be patented. At the same time I want it to involve some original research. Pretty tough situation for me. :P I need to select some ideas and let him know by the next week or so. (And yeah..he said that I can audit physics classes but the problem is my class schedule will clash with the physics department's schedule. Let's see.)

Pranav

@ACuriousMind only roll across it??

but isnt the condition for rolling v = omega r?

and a = alpha R

or in words the velocity/accn. of the point in contact with the surface must be zero

if we for example decrease the linear speed and let the angular vel. remain the same wont pur erolling stop?

what would be a good counterargument against this question, that proves it incorrect

@Pranav Precisely. And the point of contact is kept motionless by static friction.

Pranav

but infinite?