The h Bar

Q: Can total mechanical energy be a function of time?

The latter thing is a sequence, the former isn't :)

Secret

-1

Please, i am working on the effect of vibration on the mechanical properties of concretes and sandcrete materials (Flexural strength,compressive strength,Modulus of rigidity, etc). My work has application in the construction industry in terms of quality assurance during construction of vibration-...

Anonymous

2:05 PM

Confusing :P

Secret

Open system. Period

Anonymous

Okay then?

Just to clarify, "$x_n$ is a sequence" really means "$x_1, x_2, x_3, \cdots$ is a sequence". $x_1, x_2, x_3, \cdots$ are all individually real numbers; it's a "function" of natural numbers.

@Slereah god is dead scontent-lhr3-1.xx.fbcdn.net/v/t1.0-9/…

In the first candidate $1/n, 1/n^2, 1/n^3, \cdots$ is not a sequence: what is $n$? $1/n$ is not a real number.

In the latter case, you have $1/2, 1/4, 1/8, \cdots$ (by plugging in various natural numbers $r$)

Anonymous

2:08 PM

@BalarkaSen I see

That's a sequence! Every term is an explicit honest to god real number

Anonymous

Okay!

Ok, $\{1/2^r\}$ converges to $0$.

Anonymous

right

What is $\{f(1/2^r)\}$?

Where $f$ is the function I described above.

2:09 PM

You don't have to be a dick about it

Jesus is the observer

Anonymous

@BalarkaSen Thanks for the help. I think we should continue this tomorrow. Got to go somewhere. And really, thanks a lot for the trouble you're taking. I'll bug you tomorrow for this again :)

sure why not

@Slereah did you see my link

0celouvsky

Indeed.

So I should take the derivative along the geodesic and see what happens.

I did

Apparently there's a fancy name for the QM interpretation thing that conscious beings aren't special observers

The psycho-physical parallelism

2:14 PM

@AccidentalFourierTransform No, that was a First Posts review

the queue won't prompt you to flag as NAA, but it's still the right course of action

the FP queue is there to catch these sorts of things

physics.stackexchange.com/review/first-posts/172637

Im not there

ah, sorry

physics.stackexchange.com/review/late-answers/172640

^

@AccidentalFourierTransform physics.stackexchange.com/review/late-answers/172640 yes, that

yep, did you read my conv. with ACM?

basically, yes, I should have flagged

2:16 PM

@AccidentalFourierTransform haven't,no

Can I check that I'm not getting a concept of SR dreadfully wrong?

@AccidentalFourierTransform cool, just wanted to, um, flag that

37 mins ago, by AccidentalFourierTransform

I assumed that you had already flagged it

so I just DV'd it and UV'd your comment

but yes, an extra flag never hurts

@AccidentalFourierTransform ah, yeah, that does change things a bit

I got into an argument with someone a while ago, [stimulated by flat earth] that relativity means that you couldn't keep accelerating at a constant rate and feel a constant g force forever, as you'd surpass the speed of light.

I'm pretty sure though that, to all intents and purposes from your frame of reference, you could feel a g force forever and accelerate constantly, just that the rest of the universe would get more and more relativistic as you do so

2:18 PM

reasonable assumption leading to reasonable behaviour

but yeah, extra flags never hurt

and that it's only when seen from another frame of reference that your acceleration would tend to zero,

dunno if you can vote to delete yet, probably not

36 mins ago, by AccidentalFourierTransform

if E hadnt commented, I would have flagged it

Fawad

@AccidentalFourierTransform DV'd means?

You can theoretically accelerate forever in special relativity

It's called a Rindler observer

2:19 PM

@Fawad digital video

@EmilioPisanty nope

@Fawad 505

HTTP Version Not Supported

as opposed to the more common CDIV

Ignoring the energy required then, you could happily have proper acceleration continually, and experience a g force while the rest of the universe just got more and more relativistic?

@Phase the claim is incorrect

You can have a particle that experiences constant acceleration in its rest frame.

wait which claim

his or mine

oh ok nice

> relativity means that you couldn't keep accelerating at a constant rate and feel a constant g force forever, as you'd surpass the speed of light.

2:24 PM

I mean

that's incorrect

Of course, practically you can't

Thanks

For two reasons at least

Bernardo Meurer

@Slereah Need help with Portuguese?

2:25 PM

it would take way too much energy, and debris would ionise and pierce you like cheese

From the point of view of an inertial frame, the particle approaches the speed of light asymptotically.

1) you'd need infinite energy

2) the CMB becomes infinitely blueshifted as you accelerate

Yeah

You'd get cooked like a Christmas goose

That's not as terrifying to imagine as the false vacuum thing though

2:27 PM

@Phase Try e.g. §6.7 of damtp.cam.ac.uk/user/stcs/courses/dynamics/lecturenotes/…

plenty of similar resources around

Thanks!

@Slereah surely there's plenty of dust that will kill you first

yes but please don't call me Shirley

As well yes

CMB can't be avoided at all though

guys

what's a good synonym for "window"?

as in "X method offers a good window into Y phenomenon"

2:31 PM

Ubuntu

ACuriousMind

@EmilioPisanty "insight"?

Not a synonym, but appropriate in that particular sentence, I'd say

"pane of glass"