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1:00 PM
It tells you the period of it's rotation
 
6371000m
 
and $v = r\omega$
 
right?
 
so how do you think you should proceed?
uh...
 
I'm so confused lmao
 
1:00 PM
hang on
wtf
your initial message
is hideously wrong
You say that the earth has a radius of 6. something km
It's more like 6 THOUSAND km
The radius of earth is around 6371000m tho yeah
 
that's 6.371 as km
 
No
 
and 63710000 as m
 
That's 6371km
 
yh we already know it
so our equation should be
 
1:02 PM
No listen
63710000m is NOT 6.371 km
63710000m is 6371km
 
So?
 
...So...?
 
we already know what radius is
the problem is to find $v$
 
Well no the point is that the radius you started with is wrong
So if you were to use that value, then v would be wrong too
 
so you say that we ought to use 63710000m right?
 
1:04 PM
anyway now that we've cleared that up, given r in meters sub rw into v, and then compute w
You're missing the point
You want to use the value of r in meters yes, but your value of r in KM even is totally wrong
 
You stated r to be around 6km, whereas it's around 6000km
 
so hyped for this man
 
@Phase Would it be 40.075 km?
the around of earth
 
No.
 
1:06 PM
that's 63710000m then?
 
Lagranian you're saying that it would be shorter to go around the earth than to the centre of it
Which is obviously untrue
Look I feel like you're maybe getting confused by units?
convert 10km to meters for me
 
that's 10.000m
 
wait
Oh ffs
I'd recommend against using a decimal point instead of a comma
 
Anonymous
lolol
 
man
don't we need Circumference of earth
 
1:09 PM
I'm pretty sure that even though countries have their own conventions, decimal points are still preferably used for decimals
Not really, just 2pi / T
where T is 24 hours in seconds
which is 24 * 60 * 60
 
Anonymous
@Lagranian What's the meaning of that . over there?
 
Anonymous
Is that a decimal point or comma?
 
@Blue What do you mean?
 
Anonymous
@Lagranian What is the . in 10.000m ?
 
Anonymous
After 10
 
Anonymous
1:10 PM
and before 000m
 
are you talking about the question?
 
IS 10.000m TEN THOUSAND OR TEN
 
wtf
 
Anonymous
That ^
 
my god
The radius of earth is $6.371$ km. The earth is rotating around itself in $24$ hours. Then, calcuate the radial acceleration of an object that is in equador.
the question is here lol
 
1:12 PM
Idk why you're complaining though, all this is just extra conversation. I already told you how to compute it
I told you literally every step
 
phase
you told but
I got nothing
 
I told you take v = rw, sub it into the expression for a and compute a using 2pi / T
@Blue I guess he's using . as a comma
@Blue is it my imagination though or is . as a decimal point sort of accepted as standard?
 
Anonymous
@Phase May god halp him
 
my god
my brain is firing atm
 
Anonymous
@Phase Never in my 18 years of existence I saw . being used as a comma :P
 
1:13 PM
@Lagranian $v = r\omega$, yes?
 
Anonymous
I dunno if some country uses that
 
I'm gonna use this $v = r\omega$ now
gimme a min
 
Yeah but you shouldn't compute v using it
It's a waste of time imo
you can if you want tho
 
what is the easiest way then
 
Well sub it into $a$
$a = \frac{v^2}{r} = \frac{(r\omega)^2}{r} = r\omega ^2$
Then just compute $\omega$ using $\omega = \frac{2\pi}{T}$ where T is the period in seconds and you're done
Although
Idk where Ecuador is
Is it on the Equator?
I hope for your sake it is
If it's not, you'll have to use $r = r\sin (\phi)$.
 
1:18 PM
Yes That's in equator
I mean the line
the omega is $\omega = 530.9166666666667$ right?
 
nooooooooooooooooooooooooooooooooooooooooooooooo
noooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo
 
my god
 
@Lagranian WHAT NOTATION DO YOU EVEN USE
:(
anyway, regardless of notation, that value for omega is wrong
You're dividing 2pi by 24*60*60
 
I swear
my brain is firing
Won't we use $\omega = \frac{2\pi}{T}$ to compute $\omega$
 
You do
It's just you made a mistake somewhere
 
1:22 PM
Where did I do mistake
tell me let me fix up that
 
your value of omega would imply that it takes a fraction of a second for the earth to revolve
Idk where your error is but I told you what to do
divide 2pi by 24*60*60
 
Anonymous
Can you divide 6.28 by 86400 ? @Lagranian
 
Wait I've seen where I did mistake
 
Anonymous
What is $$\frac{6.28}{86400}$$ ?
 
I thought that $2\pi$ is radius
 
1:24 PM
No, $2 \pi r =$ circumference
 
@Phase Exactly, that's why I did mistake.
 
by the way Lagranian, if I may Pique your interest for a second
 
@Phase How to find $T$?
Is that 24*60*60
 
Have you ever considered the centripetal acceleration and the fact that it takes away from your weight?
Yes, T is the period in seconds
 
$T$ is $84.600$ then
 
1:27 PM
$\omega$ is defined as the 'angular velocity'. It's a measure of angle per unit time, so if you take any angle travelled [as long as its travelled at a constant rate] and divide it by the time taken for that, you'll get $\omega$.
Idk, probably. Sounds right
 
@Lagranian No, it's $86400$ (you swapped the digits)
 
I'd really recommend you stop using the decimal though
@Mr.Xcoder he's using the decimal as a comma
 
Okay, right.
$\omega = \frac{2\pi}{T}$
 
O
I didn't even see that
 
from this
 
1:27 PM
@Phase Not talking about that, the order of digits in wrong
 
yeah I didn't notice
 
ok then
 
Anonymous
@Lagranian Please stop using a decimal point as a comma
 
eyes were drawn by the purrty zeroes on the end.
 
And Hi! btw
 
1:28 PM
$\omega = 43200$ right?
 
Who moi? @Mr.Xcoder
 
from $\omega = \frac{2\pi}{86400}$
 
if so hi back!
 
Anyone.
 
....
How
Do you get a larger number than 2pi
by dividing 2 pi by a number greater than 1
 
Anonymous
1:29 PM
@Mr.Xcoder Hi. Seeing you after long...:)
 
@Lagranian How come you divide something roughly 6 by 86400 and get 43200?
 
Did you half the period...?
He divided the period by two for some reason
 
@Blue Long time no see indeed. Code Golf takes away most of my (other) free time :D
 
Wait I know that $T$ is $86400$
then I plugged it into the equation
 
Yes.
 
1:30 PM
$\omega = \frac{2\pi}{86400}$
 
Correct...
 
which will give you a very small number
on the order of 10^-5 prolly
 
Namely $0.00007272205217$
 
Anonymous
@Mr.Xcoder So, learning any new stuff lately ?
 
Thermodynamics
 
Anonymous
1:30 PM
Nice!
 
And fluid mechanics. How are you?
 
Anonymous
I'm good :)
 
I see
 
Anonymous
Thermo is one of my favourite topics :D
 
Anonymous
We can discuss someday if you find some interesting problem
 
1:31 PM
Oh really? I like it too
 
Anonymous
Yeah, especially statistical mechanics
 
by the way
 
I do however tend to like classical mechanics more
 
$\omega$ is $0.00007272205217$
right?
 
Correct
 
Anonymous
1:32 PM
You should look up the Monte Carlo algorithm and Wolff algorithm sometime (if you didn't already)...it's related to thermodynamics and statistical mech. Also it's "algorithm", so I hope you'll like it :P
 
Great now we know what $\omega$ is.
from $\omega^2r$
 
@Blue Will keep in mind
 
we get $0.92662438875014$
right?
 
that seems a little large
just a factor of 3 or so tho
 
Is that correct?
 
1:35 PM
Our school curriculum tends to be rather odd, since we study kinematics in the 6th grade, then mechanics in the 7th grade, then thermodynamics, fluid mechanics and electricity in the 8th, then in the 9th we go back to mechanics (because we couldn't learn more about acceleration and stuff because the mathematics curriculum is even weirder)
 
I wouldn't say so
it's too large
It's the right power of 10 though.
 
Where did we go wrong?
I did all correct.
 
Anonymous
@Mr.Xcoder It was similar in our school. It's good to gain a basic knowledge of all fields in physics and then build upon previous knowledge. It's not necessarily bad
 
It's not bad, but it's a bit odd
The thing is that we have to learn acceleration from the 7th grade rather than the ninth grade if we want to take part in competitions, and it's boring afterwards
 
@Blue Huh? That’s standard European.
 
1:41 PM
Question: Is the formula of the centrifugal force $\frac{mv^2}{r}$, whereas $r$ is mass, $v$ is velocity and $r$ radius? FWIW I cannot completely remember it
 
Yeah
 
Anonymous
@Mr.Xcoder Yeah, that's true. I think you're too young to worry about school grades anyway. Go ahead and learn whatever you want to learn by yourself. It's difficult to find time to learn extra stuff once you're in college.
 
It's just centripetal acceleration multiplied by mass
 
Anonymous
@0celo7 That's such bad notation....
 
Since the centripetal force and centrifugal force must cancel out in a non inertial frame like on the surface of the Earth
@0celo7 its trash
 
Anonymous
1:42 PM
@Mr.Xcoder Yes. It's a pseudo force
 
@Blue FWIW I don't need to learn all by myself, since I have a great professor and we have additional preparation (3 hours) on Sunday, as well as other 3 hours during the week, and we work at a very high level compared to the rest of the class (of course there are more children passionate about Physics other than me, and we form a great team :P)
 
Anonymous
@Mr.Xcoder Awesome!
 
@Blue It's their cultural heritage
have some respect
 
Anonymous
@0celo7 What do they use for decimal, then?
 
Anonymous
@0celo7 Okay, if you say so :P
 
1:45 PM
@Blue comma ,
 
Anonymous
Sorry, if that's true
 
Anonymous
@Mr.Xcoder ......My whole life was a lie :P
 
@Blue 1 million: 1.000.000
 
@0celo7 Don't worry about cultural heritage, I have to use it too (since I live in Europe), and still think it's trashy :D
 
It's why the UK went through Brexit
The disagreement over commas and decimals
 
1:46 PM
@Phase ACO got the series back on track.
 
Really?
 
It's not nearly as good as AC2, of course
 
I would get it but..
The performance
 
I recall a meme regarding the UK leaving Europe twice in the Same week (Brexit and losing a match at the European Football (?) Championship) :D
 
Yeah I had a few hard crashes last night
 
1:47 PM
I can't support the practices of a company that willfully destroy people's experience of the game just to try and delay a cracked release
It's because of the two DRM's they have
 
I think it was because I was running my CPU overclocked for hours
at 100%
 
@Mr.Xcoder no-one stopped to think about the consequences of Brexit really.
I mean just look at this
 
@Phase I bet if I turn down AA my fps will go way up
 
@Phase ಠ_ಠ UK
 
You should get it
 
1:49 PM
Yeah but you shouldn't have to that's what pisses me off
What chokes first, cpu or gpu?
 
GPU in the country, CPU in the city.
My CPU is weaker than my GPU
I'm thinking about upgrading
 
What OS do you use?
 
...Windows
What else would one use
 
What CPU do you have?
 
@Phase R5 1600X
 
1:51 PM
R5...? Radeon?
 
Anonymous
@0celo7 I thought you use Mac?
 
of course... Get rid of windows and enjoy life!
 
Ryzen
@Blue I have two computers.
 
Oh, is't that the meme that came out a while ago?
Or was that the Zen
 
And I use Windows, Mac, and Linux
I am multicultural
 
Anonymous
1:51 PM
@0celo7 Means you aren't a whole-hearted apple fanboy
 
Anonymous
Noice
 
Never said I was
 
@Blue I am instead :-)
 
You [redacted] [redacted] keep attacking me as though I was
 
huh
cant find any benchmark tests of mine against yours
 
Anonymous
1:53 PM
@Mr.Xcoder I'm not sure we can be friends anymore :P
 
Anonymous
Okay, I'm joking XD
 
@Phase Problem with AMD is the single-core performance, which is important for some games
 
Lol did I find it wrong
 
not sure about this one
it seems to be using every core
 
$\omega$ = $092662438875014$
 
1:53 PM
so it's just awfully programmed
 
from $\omega^2r$
 
wonder if they'll fix it
would be nice to get a steady 100
 
@Blue xP... come on we still both like thermodynamics :P
 
Nvm found it
Im on a laptop so mines as-expected weaker
 
@Phase Are you sure?
I've used all equations you showed.
 
1:55 PM
@Phase Oh I also have an 11% overclock.
 
@Lagranian im pretty sure.
@0celo7 dang it
I can run witcher on virtually full ultra
Is ACO that much a fucking tanker
 
Your GPU doesn’t crap out?
I can only get 100fps on ultra in Witcher
 
Nah, my GPU isn't too bad, again it's limited by laptops
 
Full ultra
 
I set a limit to 60fps anyway
 
1:56 PM
Hairworks, etc.
 
I dont wanna spoil myself
Oh I dont use Hairworks because I dont think its worth it
 
That’s like 10 FPS lol
 
Exactly, its fine as long as you dont get accustomed to like 100+ fps
which is why I dont
 
Ok playing ACO again, i hate you for making me do this
 
I spend a lot of time playing fighting games
 
1:57 PM
@Phase it IS an issue dude
 
so 60fps is what I'm naturally acclimatised to
 
I played old splinter cells last weekend at 185
 
I really cant decide whether to try ACO or not
 
Now ACO at 85
 
Its not as if I can even be guaranteed I can get a refund if it tanks
 
1:57 PM
My eyes are bleeding
 
Man up boy
 
Damn, that could be flagged
 
goes in time using my [redacted] to flag
@0celo7 what are you actual benchmarks?
 
I’ve done a passmark test but I don’t remember the score
13.something for the CPU
Eh
 
I am too lazy to search, so is the period of a pendulum equal to $2\pi\sqrt{\frac{l}{g}}$ or am I mistaken?
 
2:02 PM
@Phase GPU is 14,121
 
hang on gonna close chrome for benchmark
cus that thing eats cpu like nothing else
 
Now I don’t remember if I overclocked for that number
Looool they bury you with the hidden blade
 
Poll: What is your favourite subject after Physics (or if Physics isn't your favourite, which is)?
 
wait
crap used wrong tool
RIP
yeah I dont think I can commit to ACO
 
0
Q: Can't logout from stack exchange

fahdI can't log out from stack exchange in browser .in pc and mobile. Afted loged out when i open the site again it appears as i am already loggedin. I have not enabled to remember my password

 
2:12 PM
Maybe if it wasn't a piece of shit because of DRM
 
hello
 
hey
 
The gameplay is really
really
good
my god phone
I need a new phone
I just shot a guard in the head with a bow and hid him in a bush! Incredible!
Such tactics
 
Surely there must be some coding/programming project you can do that is related to your field of research. — Peter Shor 1 hour ago
my god
the irony
 
Yeah but the performance is inexcusible. The best bit is that I keep finding articles online praising ACO for it's port...
 
2:25 PM
@EmilioPisanty why?
 
@0celo7 not sure
but being told to "c'mon, just program something" by Peter Shor has to count as a minor life event, no?
 
Oh, for sure
I was doubting the irony part
 
Program Shor's algorithm
 
Anonymous
Oh wow, the MIT guy. Didn't expect him to be on SE
 
though I guess it doesn't quite beat this one
71
Q: Was the reduction in Shor's algorithm originally discovered by Shor?

Philip WhiteThis is a "historical question" more than it is a research question, but was the classical reduction to order-finding in Shor's algorithm for factorization initially discovered by Peter Shor, or was it previously known? Is there a paper that describes the reduction that pre-dates Shor, or is it ...

one of the all-time highs of SE as a format in science if you ask me
 
2:31 PM
I dont get it
what do you mean @EmilioPisanty ?
I'm an SE plebian
 
@Phase you've seen who wrote the accepted answer, right?
 
Yeah
I just don't get the whole "just program something" comment or the one about it being a "high of SE..."
maybe im just slow today
 
@Phase Shor's algorithm is the foundational result of quantum computing, at least in the sense of "it made people realize this had any potential at all" if nothing else. Getting an answer from Peter Shor about his frame of mind when he wrote is about as straight-from-the-horse's-mouth as it gets.
 
oh I see
 
Anonymous
 
Anonymous
2:41 PM
Is choosing this kind of a contour wrong for integrating $\int_{0}^{\infty} \frac{\sqrt x}{(x^2+1)^2} dx$ ?
 
Anonymous
They used that for finding $\int_{0}^{\infty} \frac{\ln x}{(x^2+1)^2} dx$
 
Anonymous
But used a keyhole contour for this one
 
@Blue there's nothing immediately wrong with it
so long as the circle at infinity converges
which looks dubious
no, wait
looks OK for both
 
Anonymous
@EmilioPisanty I mean the contour chosen in the picture I uploaded is used by the author to find $\int_{0}^{\infty} \frac{\ln x}{(x^2+1)^2} dx$. It works fine for that. But when he is integrating $\int_{0}^{\infty} \frac{\sqrt x}{(x^2+1)^2} dx$, he uses a keyhole contour. I don't know what was the need to switch
 
Anonymous
@EmilioPisanty Yeah, same here
 
Anonymous
2:45 PM
I think this:
 
Anonymous
 
@Blue well, you can do the integral with the half-circle contour and see whether you get the same
 
Anonymous
Should work for both
 
Anonymous
@EmilioPisanty Yeah, checking that...
 
using keyhole contours for either looks like a nightmare though
that pole embedded in a branch cut?
no thanks
 

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