Has anyone tried to shove the weak and strong forces into GR? I know EM is trivially in it, but don't know about the other 2.

>>16534732
>and
or*

>>16534732
The strong and weak forces require quantum field theories. We have had no luck incorporating any QFT into GR.

>>16534478
All the tea components I was originally interested in are water soluble. This does not rule out the possibility that the first steeping is enriched relative to the second steeping for kinetic or equilibrium reasons. I can't find anything on the oil dispersion mechanism.

Have quantum vaccuum fluctuations ever been measured in space? Do they vary with their proximity to matter?

>>16534744
>We have had no luck incorporating any QFT into GR.
effective qtfs can be incorporated, just not at the high energy limit.

>>16534810
> quantum vaccuum fluctuations
Depends what exactly you mean by that. We have measured the Casimir effect which would not happen without vacuum fluctuations. It's also the basis for Hawking Radiation but that is so weak, if it actually exists, we are unable to measure it. I guess the largest scale proof we have is the oscillations visible in the CMB.

Couple questions
1. What is wrong with the slit experiment where a laser shows interference patterns when shot one particle at a time? Like, what is the confusion here exactly? And why is that considered weird? If you watch this on mute it shows the setup pretty well https://www.youtube.com/watch?v=0ukdaIComZc
2. People use the world qubit to mean a quantum bit within a circuit for calculating quantum thingies. What is a qubit physically speaking?
3. People claim quantum bits can be entangled and then separated and then observed apart from each other and it collapses something. What exactly is physically collapsing? I can just write a 1 or 0 on two peaces of paper and give them to a friend and once he reads one he knows the other matches and the mystery collapses, but nothing else does. What's up here?
4. What is a quantum circuit, really? Wikipedia said something about how you can know the input of the gate from the output given. Is it something along the lines of a bunch of logic gates that feed forward but also simultaneously feed backwards and thus allow a function to settle into a solution rather than blurt out a solution? I just don't understand what's going on there.

I have a hard time understanding these things because there are 3 groups of knowledge on this. There are people who know the words and the pop culture regurgitated meanings of those words. There are people that know the math behind it and can actually use the computer terminal on these things. And there are people that actually understand what is physically happening within the circuit, they know the behavior of the materials and why they're setup the way they are.

Plz help. tysvm.

>>16534844
1. That video has nothing to do with either a single or double slit experiment. It's a delayed choice setup. So I have no idea what you are actually asking about.
> What is a qubit physically speaking?
2. What ever you can put into a two-state superposition. The physical hardware is almost irrelevant.
> What exactly is physically collapsing?
3. The wavefunction describing the entangled system. If that is physical or not, no one actually knows but it doesn't stop quantum computers doing their thing.

I've skip a lot, I know. But frankly most of your latter questions would require pages and pages of text to explain or entire term-long YT playlists. All you're going to get here is short pop-sci answers. This is /sqt/, not a graduate level physics course.

is borosilicate glass used for most experiments that involve heating strong acids and bases? i want to do hydrolysis experiments which involve heating these solutions, but i can't use a metal pot for the acids. i also heard that glass isn't good for heating strong bases.

are there parasitic primates?

>>16534884
Do NEETs dwelling in parents' basements count?

>>16534884
>are there parasitic primates?
I really wish I could answer that here, anon.

>>16534884
Considering what is Homo sapiens sapiens doing to this planet I am inclined to say ”yes".

>>16534796
>It is probably clearer to write the first term it in its more usual form 'E/c' where E is then the relativistic energy.
How is that any clearer tho? E makes sense, but what does it mean to divide it by c?
(And why does every retard who sets c=1 keep calling E/c the "energy," when it makes no sense dimensionally?)
I mean, mc at least makes a little more sense, even if it does technically imply that the particle is travelling through time at the speed of light

>>16535132
faggy answer

I wanna get into go. Should I read some theory book to start, or just go play people online?

>>16534688
Does the positive half of the real number line count as a region or open connected set in the complex plane?

>>16536523
no

How the hell does carbon dating work?

"scientists have dated the artifact to around 4000 years ago"

How does this test give me an estimate of when the tool was made, and not give the age of the stone or the wood the tool was made of? This ruin is 3000 years old but the stone is millions of years old, wouldn't measuring the carbon tell me the total age of the stone?

>>16535624
When you play people online you will be learning mistakes the hard way when they deploy strategies against you. Better to just read a book, unless you are just trying to hard stat check yourself.

>>16534688
Mathfag (1st year in gradschool) who wants to learn biochem here, should I start studying QM, EM and Thermo (and if so, from what books?) or go straight to an introductary chemistry text (and if so, what?). Moreover, does higher math even have any applications to biology?

In Newtonian physics, is there any relationship between
>the conservation of momentum
[math] m_1 \left( \begin{matrix}
1\\
v_1
\end{matrix} \right)
+
m_2 \left( \begin{matrix}
1\\
v_2
\end{matrix} \right)
=
m_1' \left( \begin{matrix}
1\\
v_1'
\end{matrix} \right)
+
m_2' \left( \begin{matrix}
1\\
v_2'
\end{matrix} \right) [/math]
and the concept of
>frame invariance [of length]
[math] \left( \begin{matrix}
1 & 0 \\
-v & 1
\end{matrix} \right)
\left( \begin{matrix}
t-t\\
x_1-x_2
\end{matrix} \right)
=
\left( \begin{matrix}
0\\
x_1-x_2
\end{matrix} \right) [/math]
, or even just frame shifting?

>>16536692
If you're just doing biochem, do a dedicated biochem book. Nothing wrong with learning physics, but physics isn't biochem so there's gonna be a lot you're not gonna need and you'll be wasting time.

If you want physics texts, read Griffith's QM and EM - those are standard introductions, and very good. For thermo, there's no real standard. You could try to find one with good focus on biochem or chem topic, but i think most thermo books will always have something on chemistry since it's so relevant, prob around the Gibbs Free energy chapter and phase changes.

>>16536583
Carbon dating only works for once living things, since all living things need to intake carbon to survive. Once they stop living, they stop consuming new carbon, which means the old carbon left over decays.

If you want to date a rock or other stuff, there are other radiometric dating methods like lead or uranium.

>>16536751
No. I'm not even clear why you would think there would be?

>>16536952
Cause a Hamiltonian invariant to position implies momentum conserved in time. But I don't want hamiltonian.

For Newtonian, cause for all [math] V [/math],

[math] m_1 \left( \begin{matrix}
1\\
v_1 - V
\end{matrix} \right)
+
m_2 \left( \begin{matrix}
1\\
v_2 - V
\end{matrix} \right)
=
m_1' \left( \begin{matrix}
1\\
v_1' - V
\end{matrix} \right)
+
m_2' \left( \begin{matrix}
1\\
v_2' - V
\end{matrix} \right) [/math]

Clearly this is a shift in frame. But idk how the shift-in-frame-of-position matrix (length is invariant) leads to a conservation of momentum, or vis-versa.
(If this works, then you should be able to do this with rotations too.)

>>16536971
>idk how
*if it is true

>>16536971
> idk how the shift-in-frame-of-position ... leads to a conservation of momentum
You are getting into topics related to Noether's Theorem. I believe you can write the action using the Hamiltonian instead of the more usual Lagrangian though I am not familiar with it at all.

>>16536971
>>16536952
Also, for Special relativity, you can do a Lorentz Transform frame boost that preserve the inner products

(x,x) = (Ax,Ax)
(p,p) = (Ap,Ap)

>>16536983
im just more wondering more about the relationship between the frame-change matrix and if it at all or with any other conditions implies a conservation of momentum, in a more explicit form then just putting out Noether's theorem on the table. I just want to stay in Newtonian. If feels like energy has to be associated somehow (mass conserved), so I'm hoping someone knows the connection

Is there a scientific explanation why my mom sometimes has days where she is super pissed for no reason? She is long past menopause btw.

sup guys
my daughter has to make a 20 minutes oral
presentation about maths as her final high school exam and she asked me for some fun ideas but since I'm a retard I'm asking you
(her physics presentation will be about molecular cuisine)

>>16537166
is she eating and sleeping correctly?

>>16534884
I will say that the difference between a predator and a parasite is not a binary classification but a spectrum.
Humans are evolving from predatory mainly predatory practices to parasitic practices.
Humans mechanism of parasitism is memetic and semantic in nature.
A human parasitizes the semantic structure of another human in other to obtain benefits.

If you know the angle of the Euler's disc relative to the surface it's rotating on, would you know how many revolutions per minute it's turning around its central axis (just to clarify what I mean by central axis, imagine it was like pizza and the central axis went through the middle being perpendicular to the pizza surface)?

Is there a formula for that and how would you figure that out? Or would you need more information than just the angle of the disc?

Another question. Imagine you know things like the force of gravity, the mass of the disc and its dimensions. Is it possible to have the frequency of wiggles as a function of the disc's angle (one wiggle being defined as a point on the circumference losing contact with the surface and making contact with the surface again)?

>>16534688
Why won't this nigga vibe?

>>16535624
online-go.com has both puzzles and basic theory, I recommend going through their Learn to Play Go before beginning one of the puzzle tracks, like 'Cho Chikun Encyclopedia of Life and Death' series they host there. It's based on the book with the same title. Name's a bit odd, but the contents are basic to intermediate.
If you want to jump straight to playing, choose matches on 9x9 board. Easier to understand the picture, quicker to finish.

>>16537354
Because the dude isn't rational.

>>16537274
The revolutions per time is related to the magnitude of the angular momentum. The angular momentum as a vector changes in time to the torque at the point of contact. This gives you an equation that you can use to solve for the revolutions per time in terms of the angle.

How do I prove this?
[eqn]\int_{-\infty}^{\infty}\frac{\sin^2(x)}{x^2}dx=\pi[/eqn]

>>16537527
https://math.stackexchange.com/questions/13344/proof-of-int-0-infty-left-frac-sin-xx-right2-mathrm-dx-frac-pi2

how can i find the solubility of ammonia in water or methanol at -50c and 200mbar? i can't find any data below 0c or 1bar
i think if i at least had data at the right temperature, i could use henry's law to account for pressure, but that data doesn't seem to exist either
is using van't hoff and then henry's the best approach? how accurate will it be?

i don't know much about chemistry. i could be missing something obvious

>>16534844
I don't have an answer to your questions, but in regards to your video about light and beam splitters, is the polarity of light essentially the current 'phase' experienced by the light?
If light behaves like a sine wave, is polarity determined by the wave 'going uphill' vs 'going downhill'?

And I think I've typically seen light's movement represented as a corkscrew/spring pathing, but is that just me misinterpreting the information, or would is it more accurate to describe it's movement as 'helical' in nature?

>>16537211
High schoolers know about complex numbers, so go beyond that and talk about other types, like dual numbers or split complex or quaternions or other hypercomplex. She can talk about the different ways to represent and write em when you move from a 1x1 matrix to a 2x2 or higher matrices. You can go beyond to Clifford algebras so now there are multiple versions. You can talk about a generalized Euler equation that leads to more generalized rotations. You can talk about how Euler's equation is the exponential map for a manifold that exponentiates a Lie group of objects to a Lie algebra, so like how you can use exponentiate quaternions to get an algebra of 3d rotations, so now you can rotate 3d objects like how high schoolers know normal complex rotates 2d when you take i*theta and exponentiate it. You can talk about how you can rotate spinors, and what the hell spinors are. At this point it's gonna be longer than 20 minutes so wtv.

If you want to stay with complex numbers, you can talk a bunch about the Riemann zeta function like it's development and how it became so important, and maybe generalize to L functions at the end.

Could also talk about group theory, algebras, or geometry. She doesn;t even need to learn much - just read a wikipedia on anything interesting and talk for 20 minutes

>>16537706
exponentiates a Lie algebra to Lie group*, my bad. Rotations are the groups, i*theta is the algebra

>>16537683
>i could be missing something obvious
You could indeed. Below 0°C, the water would be solidified as ice.

>>16537216
Now that you mention it, she doesn't sleep very well. But that's normal for old folks, isn't it?

>>16534874
BUMP!!!!!!!!!!!!!!!!!!!!!!!!

How do I solve these kinds of problems? Do I just make random derivations and hope for the best or is there some algorithm to check if a clause is derivable or not?

Is it isomorphic to Z/p(p-1)Z? If no, what group is it isomorphic to?

p is prime, of course

>>16538360
I don't really know the field so I can't help here, but what is the answer supposed to be? I feel like it's b but since I don't know the actual intent/meaning behind the question that's basically just a guess based off of familiar syntax

lets say i have two functions, and i multiply them together and integrate over the entire domain to get a scalar, i.e.
[math] \displaystyle
k = \int_{- \infty}^{\infty}f(x)g(x)dx
[/math]
clearly this isnt exactly invertible; if i have k and f, theres infinitely many solutions for g. however, what if i assume g is a (finite) linear combination of some other known functions? i.e.
[math] \displaystyle
k = \int_{- \infty}^{\infty}f(x)(a_1g_1(x) + a_2g_2(x) + \cdots + a_ng_n(x))dx
[/math]
how would i go about finding a solution (or all solutions) for the coefficients?

>>16538401
You can derive all of them.
You pick two clauses, and if they have both the positive and the negative version of a number, that number get canceled. Like:

(6 -1 3) and (-6 -4) = (-1 3 -4)

and you try all the possibilities to verify if you can get to those options or not.

>>16538430
Interesting, thanks for the info, I think the easiest way in that case would just be to try and reverse engineer
Final state (1), find everything that has a 1 in it and try and cancel

>>16538423
> theres infinitely many solutions for g
By that logic there should also be an infinite amount of solutions for each [math]g_n[/math].

>>16538520
the functions are known priori, the solutions refers to the coefficients.
at any rate, i think i figured it out. for my original problem, if g is a linear combination of one function then youre just solving
[math] \displaystyle
k=a_1\int_{- \infty}^{\infty}f(x)g_1(x)dx
[/math]
if you add another coefficient then you have a 1D family of solutions. if you add another f and another k then youre back to 1 (or zero, or infinite) solutions. you can express this with pic rel (i changed g to f and f to r), where [math]C_i\{f\} = \int_{- \infty}^{\infty} f(x)r_i(x)dx[/math], with the matrix being easily invertible.

>>16538528
>where [math]C_i\{f\} = \int_{- \infty}^{\infty} f(x)r_i(x)dx[/math]
oh, and chatgpt tells me thats called an "inner product", apparently

>>16538368
no but to
> Z/pZ x Z/(p-1)Z

Love math but I have a hardtime parsing word problems. Am I fucked?

>>16537706
thanks

>>16539993
>word problems
Aren't you too young to be thinking about getting fucked?

>>16539993
If you have an example you struggle with, post it

Eh, that's more of a "can you read" issue, which having worked with people, I know this is sorta understandable. If you can do math well, then you're at least halfway there. Half of reading is separating the wheat from the chaff and the other half is re-writing the valuable English words into understandable math language. Like, oftentimes, the words in a given problem has nothing of value, so you gotta learn to ignore it - but this more a reading strategy than a math one. Then with only relevant sentences remaining, you gotta be able to translate each one into a math sentence, which takes practice and understanding of math. Finally, you need to make connections between the variables you've created. The entire time, the steps you take need to be guided by your own understanding of what the hell you're even trying to solve for.

For a very difficult problem, it's best to parse through each sentence, ignoring the useless ones and translating the useful ones into math writing. At the end, you write out what you're solving for (and in what form!). Then you analyze the information you've just written down, trying to make a connection to them and the end goal. Tips to analyze and make the right connections are
>working backwards from the end goal and connecting it to the rest of your info
>recognizing units (unit analysis) to guide the form of your equation
>determining how many unknowns there are, which tells you have many equations you need
>perform "uniqueness testing" and ask yourself, is this individual aspect of the problem unique? (This helps for the tip above)

For a very simple problem, it's common to basically memorize what you've just read because the problem is so short, figure out what you're trying to solve for (and in what form!), then write out an equation, filling in the blanks with what you memorized. So no need to waste time and write down too much.

Also, do practice problems

>>16540462
Appreciate your post anon.

I think my problem is that i have a really good memory and as a result have relied too much on memorizing a process. I've done my best to develop the intuition necessary to solve those problems without memorizing but physics and stats problems screw me time and time again.

Ive got a couple of stupid biology question I hope you guys can help me with.

I’m trying to understand how disuse atrophy works in muscles for people who have a sedentary lifestyle, I understand that when youre just lying around then your body breaks down the muscles that it’s not using, I just don’t know why or how biologically. What is the process?


Secondly, when someone is starving and the body starts breaking down the muscles for energy, why and how does it do that? I thought cells only produced ATP from glucose and ketones.

>>16540670
You need to understand that all of your cells are constantly simultaneously disassembling and reassembling themselves. It doesn't seem like it would be efficient, but the systems that build that place the proteins never shut down, and nor do the ones the remove them and break them down.
Your body uses chemical signals to tell cells to build faster or slower. When you sit around, the disassembly outpaces the assembly. When you work out a lot, the assembly dominates.
When you starve, other systems grab up the free building blocks, so the cells don't all have enough to replace everything. Eventually your organs fail.

Is it true that embers from a fire teleport/phase through other material and the studyof them is what leads to the understanding of that concept? I've seen them teleport through stone, steel, and glass. They seem to not be able to pass through organic matter like plants and animals but instead just burn then, so my intuition led me to that theory.

>>16540952
>Is it true that embers from a fire teleport/phase through other material
Absolutely not. Embers are just glowing particulates. You are describing things that sound like they belong more on /x/ than here.

>>16537211
Just make a presentation about a weird badass integra and a method to solve it, it should take at least 20 minutes and your daughter can use a whiteboard pen and eraser for it without going further shit that doesnt make sense to learn if she isnt going to study math related careers.

>>16540265
uuoohh

hello sci. there are many fields of math. but are all of them good?
you may have noticed that different branches of mathematics arrive in completely different ways to similar structures or theory, and that these apparent connections are later proven, revealing the two structures were the same all along. i guess the normie-approved example would be monstrous moonshine, where an obviously useful, good, and nice field of mathematics which arose naturally out of need was proven to have deep similarity to the absolute disgrace that is the shitty hell-world of group theory, wherein there is only masturbatory invention of novelty for the sake of novelty.
if this is the case, that is, any field of math may eventually reach any conclusion, is it not also the case that all math must therefore be equally valid and good?
or, is the opposite instead true, that purity in mathematics must be pursued even harder, as one will more easily reach useful structures through the application of the correct field (instead of jacking off to groups or topology all day for no reason)?

>>16541989
ah yes, we all love bot posts.

>>16541993
just because im dumb doesn't make me a robot :(

any good introductions to gauge theory? especially as it applies to condensed/quantum matter?

my friend says I talk too abstractly, is he just dumb

>>16542284
Sounds like you are a midwit

Okay, this is about science fiction, but I'm going for some amount of basic plausibility:
Given tech more advanced than ours, is it possible to make man sized armor, even if it is very heavy and requires assistance to move, that can withstand both gunfire and intense heat and energy (as in from a laser gun)?

Would it be plausible that such a suit would be able to detect when hit with a laser and vibrate or otherwise notify the wearer since it might be possible, before the heat gets you, to not notice a laser hitting you in the heat of battle (where as gunfire, if for nothing else than the noise and (if heavy enough to damage the armor) force of impact is a bit more obvious?

Will it be logically truthful if one says that this is "the box with oranges"?

>>16542635
Not unless this is the only box with oranges.

>>16542638
So "box with oranges" and "box with only oranges" are equivalent?

>>16542672
No. Obviously we're getting into connotations, but I'm going to assume you really, really care about being technically correct.
A box OF oranges would be a box with only oranges.
That box with oranges refers to a specific box that has at least two oranges in it.
The box with oranges is the only box that contains oranges in the context of the conversation.
A box with oranges could be any box in the room/warehouse/location that has oranges.

>>16542683
OK, so if we imagine a box with 100 oranges and 2 apples at the bottom, calling it the "box of oranges" would also be incorrect then, wouldn't it?

>>16542720
It is not a box purely of oranges, but without the foreknowledge that it is a box that also contains apples, I don't think anyone would bust your balls over it. But I would think it to be incorrect if you knew about the apples to not mention them.

>>16542284
Classic midwit (you, that is). Try applying some of that knowledge sometime.

>>16542720
the box of oranges and apples and oxygen and nitrogen and microplastics and escherichia coli and staphylococcus aureus and pseudomonas aeruginosa and wood splinters and argon and carbon dioxide and neon and helium and methane and cladosporium and...

>>16542418
>>16542813
sounds like you guys are jelly of my abstract thinking skills, it's ok though, not everyone can think like a God

A vector [math]v=v^i e_i[/math] is sometimes just identified by its components [math]v^i[/math] and called a contravariant vector. But its basis vectors are written as [math]e_i[/math], which is notation for a covariant vector.
That's just dumb notation and doesn't mean the basis of a contravariant vector are covariant right?
Why do they write it like this?

>>16543495
Partly notation, partly not. After all the covariant and contravariant bases are what form you dual basis but they do not transform in the same way as the vectors themselves.

>>16543510
But a vector lives in a tangentspace. And the basis vectors live in a tangentspace too, right?
But following the notation the basis should live in the cotangent space.

>>16543517
> And the basis vectors live in a tangent space too, right?
I'm not sure that's strictly true. The bases define the space, they don't inhabit it like the vectors do. co-/contra-variant vectors are defined by how their components transform, again not something that applies to the bases.

>>16543527
>not something that applies to the bases
I kind of understand it in the context of tensor analysis. But when I try to match it with what I know of vector analysis my brain just throws an error warning.
For example, the total derivative [math]df = \partial_i f \,dx^i[/math] is a 1-form and its components transform like a covector. But then [math]dx^i[/math] looks like a vector, but surely it transforms like df under a change of coordinates by simply applying the chain rule.
I'm just so fucking confused by this notation. It makes following the rules on a piece of paper much easier, but I have no idea what's happening on a geometric level.

>>16534688
I've decided to take up cooking mephedrone as a hobby and I have zero chem experience. Redpill me on how to go from beginner to pro chemist.

Am I intelligent or is robot stupid?
Can you solve without dividing?

>>16543639
> Am I intelligent?
No.
> is robot stupid?
Yes.
> Can you solve without dividing?
No.

galaxy brain reporting. I feel like I could do better if I was prepared for those weird matrix questions with ambiguous patterns.

>>16544377
No online test is going to give you an accurate result, they are meaningless. You might as well just assume they are all scams. Only an in person test with a certified psychologist or better yet, at a Mensa testing center will give you a valid score.

I'm having difficulties understand the speed of light and why you can't ever reach it.
I saw a video that explained it with a photon clock in two reference frames.
Frame 1 is within a spaceship moving through space. Here the clock works as normal.
Frame 2 is observing the clock in frame 1 from the outside, here the clock is slowed down due to time dilation. The video then goes on to derive the time dilation formula and show how you either need infinite energy to reach the speed of light in finite time or you need infinite time with finite energy.
Now that's nice and all but I don't understand how the photon clock can have two different speeds depending on where you view it from.
Anyone have an explanation a dummy like me can understand?

>>16546006
>I don't understand how the photon clock can have two different speeds depending on where you view it from.
it follows from the fact that light always has a constant speed no matter how you observe it.

>>16546012
yes, I understand that.
But from frame 2 the ticks take longer than what is measured in frame 1.
And that's what I can't wrap my head around

>>16546014
because the "tick" is measuring how fast the photon bounces between two mirrors. if the clock is stationary (relative to you), then that speed is c. but if the whole assembly is also moving horizontally, then that same speed c has to be shared between the photon bouncing vertically and the photon moving horizontally.

>>16546014
wait im sorry that wasnt your question.
>But from frame 2 the ticks take longer than what is measured in frame 1.
yea, time changes speed when you move, thats like step 1 of special relativity.

>>16546020
>time changes speed when you move
But why?

>>16546023
it follows from the fact that light always has a constant speed no matter how you observe it.
imagine youre standing 1 lightsecond away from your friend, and you start traveling towards him at 0.5c at the same instant you shoot a photon at him. your friend would observe the photon traveling 1 lightsecond in the span of 1 second, so he would measure the speed of the photon to be c. but from your point of view, the photon would have only traveled half a lightsecond away from you. in order for you to also measure the speed of the photon to be c, it must be the case that only half a second has passed since you fired the photon. therefore, traveling at 0.5c has caused time to slow down for you by a factor of 2.

>>16546030
That explains that logically the statement has to be true but it doesn't explain WHY it's true.
Which leaves me just as confused as before.

>>16546072
iunno bro thats just how it be. ask god why he made massless particles always travel the same speed.
or maybe theres an explanation in QFT but youll have to ask someone else for that.

>>16546006
>>16546072
You can show that the speed of light is a constant in all reference frames from Maxwell's Equations. It is where Einstein got the idea from. Though you could then ask why are those equations true... that's physics for you.

> I'm having difficulties understand the speed of light and why you can't ever reach it.
Using the fact the speed of light is constant you can derive the relativistic kinetic energy equation for an object: [eqn]E_{kinetic} = (\gamma - 1)m_0 c^2[/eqn]
where [math]m_0[/math] is the rest mass of the object and [math]\gamma = \dfrac{1}{\sqrt{1 - \frac{v^2}{c^2}}}[/math].

So when [math]v=0,\ E_{kinetic} = 0[/math], and in the classical limit when [math]v/c[/math] is very small you can write this is as (using a simple expansion): [eqn]E_{kinetic} = \left( (1 + \frac{v^2}{2c^2}) - 1 \right) m_0 c^2 = \frac{1}{2}m_0 v^2[/eqn] which you should be familiar with.

But now look what happens when [math]v/c \to 1[/math]. The amount of kinetic energy in the particle increases exponentially. You need to add more and more energy to the object to accelerate the object by ever smaller amounts. In fact to reach [math]v=c[/math] would require an infinite amount of energy, that just isn't physical. It can't be done.

any good resources for learning the basics of abstract algebra and group theory when one doesn't have a strong background in linear algebra and number theory?

ideally it would help me learn those too

i've been watching this youtube channel and its very helpful

>>16547035
Read Lang

>>16534688
what is /sci's opinion on systems or systems & control engineering. I've heard very good things about the specialization, and I've heard that it is the most soulless and boring human endeavour possible. I'm asking because I found a Master's program that interests me and it looks to have courses that seem pretty cool.

>>16547486
>pic
i didnt go to school to wear a fuckin hardhat. if i cant show up in flip-flops and an anime titty shirt then i aint showin up.

>>16547486
>soulless and boring
Most jobs are. The ones that aren't will give you heart disease and hypertension.
Learn how hobbies, family, and work-life balance works

>>16547583
not what I asked but whatever.
>>16547527
it's just a phote, you can be at home or in your garage and wear whatever you want while you print parts for another 3d printer you are designing

>>16547646
>not what I asked
You listed a pro and a con and I'm saying the con is trivial. It's a good career, go for it. But definitely find something outside of work.

>>16547708
of course, one of my most pleasant hobbies is engaging in intellectual discussions with random people on a mongolian wrestling forum

Should we reinvent english with rules that all words have to follow? Like no more silent letters or words like lead and lead looking the same but sounding different. And also eliminating words that have multiple meanings and giving each its own word

>>16547729
>Like no more silent letters
Which accent/register is being used to decide which letter is silent?

>>16547729
That was partially the original intent behind Esperanto, and more recently Logban - a language constructed using the rigorous mathematical laws of logic. However the latter is so tedious to use it kind of defeats its purpose.

>>16547729
>>16547753
There are regular rules between sound changes in a lot of different accents. It's plausible that some linguist could develop a simplified spelling system that works at least for several major English accents.

>>16547920
Yeah, but then you have differences in pronunciation that go beyond just regular sound changes from accent. For example, "herb" - how do you represent the fact that Americans pronounce the h and Brits do not?
Can't just make it so initial h is spoken in one and not in the other, since you'd have words like "hotel". Unless you want to make it hhotel, with the understanding that a second h is unspoken in American and spoken in British, but then... well, eventually it stops being a "simplified" system

>>16547933
>For example, "herb" - how do you represent the fact that Americans pronounce the h and Brits do not?

It's the other way round; Americans say erb.

>>16548127
I'm retarded and forgot to proofread after rephrasing a few times, but the point still stands

>>16547933
Two options as I see it:
1) Write it as "herb" (or whatever the vowel looks like after spelling reform), and just have the caveat that Americans don't pronounce the "h". Rare situations like this are not what makes English spelling confusing, it is the irregular way of writing vowels.
2) There are alternate spellings "erb" and "herb" in use, and writers use whichever one they prefer.

>>16547753
His majesty's, of course

>>16547729
james while john had had had had had had had had had had had a better effect on the teacher

Does the following suggest ASD, ADHD, or just below average intelligence?:

When I look for something while reading, I usually forget what I’m looking for. I become absorbed in the text I’m reading and forget what I’m looking for. I have to stop and think repeatedly, looking away from the text, to remind myself what I’m looking for.
Similarly, when I go to 4chan to troll, I get distracted by the content and genuinely interested in or angered at it, and then engage sincerely or just close the browser in disgust. But then later in bed, without any external stimulation, I’ll giggle as I think about ways I can troll.

A separate problem I have with reading is that I’m constantly reminded of other things by what I’m reading, and my mind goes off on tangents. I’m still looking at the text, sometimes even subvocalizing the words, but most of my consciousness is on whatever memory, imagining, or concern was conjured up by the words.

>>16548889
Everything is autism. There are no other disorders.
If you:
>wash your hands until they bleed
it's autism
>scream like a demon in public
autism
>jump off a bridge for attention
autism

Even if you cut off your dick, get tit implants, and start calling yourself a "she," it's still just autism.
The DSM is a lie.

>>16548965
But didn't the DSM getting rid of Asperger's and turning autism into ASD result in fewer people qualifying for ASD? A lot of former Aspies aren't considered ASD.

Please help! I can't solve an exercise in my Algebra book.

It asks whether there are infinitely many prime numbers p for which p+2 is also a prime number.

>>16551113
That might legitimately be one of the worst attempts at a shitpost I have ever seen.

>>16551113
This is not true. Proof is by counterexample:

Let p=7 (a prime number). Then p+2=9. However, 9=3×3 and thus is NOT a prime number. As we have derived a contradiction, we must conclude that the statement is false.

>>16551113
Yes.
Proof: Ramanujan showed it to me once but I don't remember how it goes because I was drunk as hell but he wouldn't lie to me right?

I feel so stupid for not knowing linear algebra. I feel like it holds me back. Every time it comes up in some topic it feels like a punch in the gut.

What can I do? I feel too old and dumb to learn new things.

I know what a matrix is but that's about it.

take Schrödinger's cat and put a camera in the box, recording. is it still in superposition until I check the camera? or does the camera itself collapse the function once it starts recording?
also what happens if the cat like dies and falls to one side thus making a thump that I hear? that kinda ruins the whole thing

>>16554191
> does the camera itself collapse the function once it starts recording?
no. camera are passive devices (just like our eyes) they don't emit anything to "see".

>>16554202
so camera footage is also in superposition? what if I add a computer which analyses the video in real time and makes a sound if cat dies? it shouldn't beep or continuously beep?

>>16554191
in theory, the wave function of the cat and camera would be entangled. once you observe the camera, now you become entangled as well (which you interpret as a collapse, since "you" only witness one of the two outcomes). pic related is a real experiment where an entire electronic device (the coincidence counter) is put into a superposition.

>>16554208
> what if I add a computer which analyses the video
that would work since to analyse 'something' would involved making a measurement (reading data from the camera) and any measurement (a particle interaction that involves a change of energy) would break the superposition.

you also have to remember that Schrödinger's cat is a thought experiment, in reality the air inside the box or a photon of thermal radiation would pretty much collapse any superposition instantly. the cat would never actually be in two states.

>>16554232
hmm so camera has to receive photons off the cat to make the call, and those photons would ruin the entanglement?

>>16554235
yes, but that would still happen even if the camera wasn't there.

>>16554242
ok what's a better model because the cat thing is confusing.

>>16554232
>that would work since to analyse 'something' would involved making a measurement (reading data from the camera) and any measurement (a particle interaction that involves a change of energy) would break the superposition.
its perfectly possible to take a measurement of something without destroying the superposition. in >>16554212, the coincidence counter patiently waits for the photons to reach D1/D2/D3/D4 before "deciding" whether or not the particles interfered with each other on their way to D0.

>>16554261
what do you mean by better model? actual experiments of the concept involve a single or a handful of atoms isolated in as close to a perfect vacuum as can be achieved. exactly the same idea but no cute cat involved.

>>16554280
the delayed choice experiment is a bad choice for a counter-example. the initial interpretation is now regarded as wrong but it still pervades pop-sci explanations.

>>16554286
what was initial interpretation? and what is your current interpretation of the delay-choice quantum eraser experiment?

>>16554281
oh so there's no practical way to have larger objects in superposition?
so then, are the photons themselves acting like observers? whenever they bounce into entangled particles? because they technically measure the system? like I would be poking the cat?

>>16554288
current interpretation is there is no delayed choice and there's nothing mind-blowing going on, it's simple filtering of information. I believe /sci/'s favorite ytuber Sabine has a good break down of everything.

>>16554289
> oh so there's no practical way to have larger objects in superposition?
it can be done, it's just becomes increasingly more difficult. it's the bane of quantum computers

> are the photons themselves acting like observers?
yes, exactly that. physicists used the word observation very differently to the general public and that is where all the confusion arises.

>>16554293
>I believe /sci/'s favorite ytuber Sabine has a good break down of everything.
i only watched about 45 seconds but i dont think she's going to say anything i disagree with. of course it isnt time-travel. what i was asserting is the following:
>if you are entangled with a system, you cant see it interfere with itself.
>if you are not entangled with a system, you can see it interfere with itself.
>in the DCQE experiment, the measurement at D0 is performed prior to the action/non-action of entanglement.
>however, since interference can be observed at D0 (so long as the photons took the path that prevents the coincidence counter from becoming entangled with them), it must necessarily be the case that the photons are still in a superposition, and in fact the entire D0 detector is in a superposition, when the photons reach D1/D2/D3/D4.
>therefore, it is possible to take a measurement of a particle without becoming entangled with it.
more specifically, it is possible for a human to use an electronic device to measure a particle without the human becoming entangled with the particle or device. you could theoretically use a camera to record Shrodinger's cat without the camera "collapsing" the wave function of the cat, it would just be very difficult to isolate yourself from the system.

>>16554185
Linear algebra is so fundamental that it pops up basically everywhere in math (and thus also in a lot of places outside math).
>What can I do? I feel too old and dumb to learn new things.
Have you tried your best?

>>16554344
I think you need to entangle the camera with everything which should be theoretically doable but not practically (easy). and ah yes also the light source and photons hitting the cat reflected into the camera. everything involved has to be entangled.

>>16554293
>Sabine
I found her bomb experiment interesting but don't know if I understood it correctly. it's basically extracting information about where the entangled particles AREN'T, which is extra info for the system but also doesn't break the entanglement because no interaction with it?

>>16554185
this is me but with abstract algebra.

>>16554363
Yeah. The bomb one *is* interesting unlike the so-called delayed choice eraser. You seem to be getting information out of the entangled system without actually interacting with the system.

Is it possible for the Air Force, to do cloud seeding in Hurricanes causing them to weaken or dissipate before they hit the U.S.?

>>16554496
You seem to be vastly underestimating how much energy the average hurricane contains. Anywhere between 10^17 to 10^19 Joules per day, or about 10,000 atom bombs. Good look weakening that.

I want to go through the recommended readings for biology. What level of math, physics, and chemistry do I need to do so?

Thermodynamics say that perpetual motion is impossible because there's always going to be energy loss in a closed system that will end up halting such motion eventually.

However, Newton’s third law states that “If one object exerts a force on another object, then the other object exerts an equal and opposite force on the first object”. Isn't this contrary to thermodynamics? It shouldn't be equal force, it should be a "less than equal" force.

>>16554909
Newton 3 says something about momentum conservation.
Thermodynamics is about energy conservation.
Also nobody cares about newton anymore.

I looked in the sky and I saw something the size/brightness of a small star moving across the sky, there were some larger/brighter stars around it
I tracked it crossing a number of stars heading in a straight line and then I looked down and looked up again and couldn't see it
Am I schzo, are aliens trying to fuck with me or is it just a satellite?

>>16554986
Try recreating it in stellarium
Probably iss or some gay shit

>>16554993
I'm in Australia, does that exclude the ISS?
Idk shit about space so I can't us stellarium

>>16554996
kinda

>>16534688
Why isn't there a lunar orbiter that provides realtime footage of the moon?

Also, why does my finger turn brown if i stick it in my pooper?

>>16554909
> there's always going to be energy loss in a closed system
Not true. A closed system by definition means that there is no energy lost (or energy gained).

> it should be a "less than equal" force.
It depends but such details are ignored in idealised calculations. When two pool balls collide energy is lose through sound and heat. However when two nuclear or atom-sized collisions occur no such thing happens, they are 'perfect' collisions.

Flash.
For one second you find yourself traveling at light speed. You end up about 3/4 of the way to the moon. This also just happens to be the exact point where gravity between the Earth and the Moon cancel out, because the Moon is 1/4 the size of the Earth.

Is this in any way related?

>>16555244
I don't think you know the meaning of the word exact. There are only two instances on the entire moons monthly orbit where that would be true.

I don't understand "reciprocal"-ness.
Why is the reciprocal of 5 1/5?
Is it as simple as 1/5 = 0.2, and 0.2x5 = 1 = 5/5 ?

>>16555253
yea, reciprocal is just means inverse, usually multiplicative inverse, i.e.
[math] \displaystyle x \cdot x^{-1} = 1 [/math]
by definition.

>>16555253
Taking the reciprocal means inverting a fraction. So [math]\dfrac{a}{b} \to \dfrac{b}{a}[/math]. A good example would be dividing by a fraction is the same as multiplying by its reciprocal.

This law is stating: [math]\left( \dfrac{a}{b} \right)^{-n} = \left( \dfrac{b}{a} \right)^{n}[/math].

>>16555252
26,425 difference at most. The number is still oddly close regardless of where the moon is.

>>16555739
The strong law of small numbers strikes again. No matter the distance you could form a ratio that is "close".

>>16555739
>26,425 difference at most.
so like 7%?

>>16554986
That's a satellite. There used to be less, but there's a fuckton nowadays

so i've stumbled upon the idea of "one-way speed of light" and...i don't get it
it's apparently impossible because you can't synchronize the clocks and signal has to travel faster than light yada yada. so what?
here's my setup: somewhere in the vacuum of space i prepare this. i first synchronize my both super ultra accurate clocks and then move them away from each other at the same speed until i get to some known distance. then i shoot my laser in line with both detectors, both will stop the clocks when they detect photons. i do the experiment and then wrap up everything. since i knew the distance and the time difference between the clocks, i can calculate the one way speed of light
did i miss anything?
is it because the first detector "steals" a photon and the second detector is affected by that much less gravity from the approaching one-photon-less light wave?

>>16555827
>then move them away from each other at the same speed until i get to some known distance
https://youtu.be/pTn6Ewhb27k?t=160

>>16555830
that's why i explicitly said to move both clocks at the same speed so they undergo the same time dilation. Veritasium completely skipped that option

>>16555838
i think if you keep watching he mentions that the clocks would only dilate at the same rate if the speed of light was the same in both directions.

>>16555841
>if the speed of light was the same in both directions
okay, but that's just an assumption that it isn't. probably true, as the Wu experiment showed that there's a preference in direction but now we wander far beyond the scope of this simple experiment and i feel like we're trying to use a sledgehammer to crack a nut

>>16555845
i dont know what to tell you, you cant assume the thing youre trying to prove. argue all you want that it makes things "simpler" but the fact of the matter is that isotropic nature of the speed of light is probably unfalsifiable. dont come here claiming that you found some magically way to prove something that many people way smarter than you have tried and failed to do before, only to immediately back down with "oh well isnt this getting too complicated?" because you didnt even bother to watch the fucking pop-sci video on the subject,

>>16555852
no, anon, i've watched the fucking pop-sci video. Einstein also said that this is only a convention
but again, so what? what does that change in my experiment? i can shoot the light from the other side, swap detectors, rotate my setup by 180. maybe i'll get different results, maybe they'll be the same. maybe the speed of light is different in one direction than in the other one and then the light wave compensates for that
how do we then know that the light has no "bouncing preference". maybe the two-way symmetry also isn't the same in all directions. how do we know anything about anything yada yada
none of that affects my experiment. it does exactly what its supposed to do. it measures the one-way speed of light, whatever that is in whichever direction, dimension etc

>>16555868
>maybe the two-way symmetry also isn't the same in all directions
It has been experimentally verified as such.
>none of that affects my experiment. it does exactly what its supposed to do. it measures the one-way speed of light, whatever that is in whichever direction, dimension etc
...If you assume no time dilation, and if there is time dilation it becomes completely useless because you can't determine what it is.

>>16555827
> i first synchronize my both super ultra accurate clocks and then move them away from each other at the same speed
Which due to relativity is the same as one clock remaining stationary and the other moving away twice as fast. So from that frame of reference the clocks are now no longer perfectly synchronized and that is one one you are firing the laser from.

>>16555868
>no, anon, i've watched the fucking pop-sci video.
did you skip the part where he explains whats wrong with your exact experiment?

>>16555876
see, that's why we do experiments instead of dwelling on some philosophical debates. that's why my experiment works without any reflections included
>if there is time dilation it becomes completely useless because you can't determine what it is
we do have equations that account for time dilation for a moving object though. scratch the synchronization, i can account for the difference in time using mathematics
>>16555910
okay but that works the other way as well so both are affected in the same way. consider it as being seen from a 3rd party observer
>>16555917
Veritasium jumps all over the place in his video. when he gets to my setup, he's already talking about the conventions etc. he says that the lack of symmetry in direction affects the synchronization but then says that the universe compensates for that and i still measure the same c no matter the direction, meaning that the symmetry still applies. if my setup had a mirror at the end and i'd take 2 measurements, i'd get my compensated, symmetric, doubled c so there's no reason to not get the c from a one-way trip

>>16555938
So how do you know how far apart the clocks are? Remembering that you can't measure distance or time travelled without using the (two-way) speed of light?

How long will it take me to go through all of high school math, and gain a good understanding, starting from algebra 1?
I've always been retarded in math but I want to do better

>>16555938
>we do have equations that account for time dilation for a moving object though.
...Equations which require knowing the speed of light in that direction. You can't use those if your goal is to measure that very thing.

I am trying to show lim n->inf n^b / a^n =0

i am trying to do a^x * lim h->0 (a^h - 1)/h and make it a^x (lim h->0 a^h/h - lim h->0 1/h).

chatgpt says i am breaking the rules, but i dont understand why.

here is what it said

>>16556164
First show it when [math]b[/math] is a natural number using L'hospital or Stolz-Cesaro [math]b[/math] times.
Then the general case follows from this since
[eqn] \frac{n^b}{a^n} \leq \frac{n^{\lceil b \rceil}}{a^n} [/eqn]

Any infinite discrete set is bijective to [math]\mathbb{N}[/math]. Can I state, similarly, that any continuous set is bijective to [math]\mathbb{R}[/math]?

>>16556285
can you even think of any infinite sets that aren't bijective to either [math]\mathbb{N}[/math] or [math]\mathbb{R}[/math]?

>>16556294
No, I cannot

>>16556285
No.

The set of all 0-1 sequences for example looks pretty discrete to me but it's bijective to R rather than N.
The set of all functions from R to R does look continuous to me but it's not bijective to either N or R.

>>16556285
whats meant by "continuous set" here? a set with measure > 0?

>>16556308
Just an uncountable set

>>16556309
well then obviously no, the power set of any uncountable set is also uncountable but has a greater cardinality.

Is it acceptable to write [math]p_\alpha \in X^\mathbb{N}[/math] to denote that a sequence [math](p_\alpha)_\alpha[/math] is in a certain topological space [math]X[/math]?
Honestly I really do not like the notations [math](p_\alpha)_\alpha[/math] and [math]\{p_\alpha\}_\alpha[/math].

>>16556521
Write [math](p_\alpha)_{\alpha} \in X^\mathbb{N} [/math].
Do not write [math]p_\alpha \in X^\mathbb{N} [/math] as that is all wrong since every [math]p_\alpha [/math] is an element of [math]X[/math] rather than [math]X^\mathbb{N} [/math].

>>16556542
Is there any other way to denote a sequence? The parenthesis notation is awkward since I use it for n-tuples, and the curly bracket one I use for sets a lot of times.

Are gravity wells shaped like the top well or are they shaped like the bottom well? If they are shaped like the top well, why is gravity not maximum in the center of the planet?

Everyone explains the gravity in the exact center as being 0 because there is an equal amount of mass pulling you from all directions.

If you insist that it is 0 in the center, why does a black hole have a singularity in the center instead of 0 gravity?

>>16556745
> why is gravity not maximum in the center of the planet?
Imagine yourself at the center of the planet then ask where is all the mass? Answer is, it's all around you pulling equally in every direction resulting in a net-zero force.

>>16556745
>>16556758
Forgot the rest:

> If you insist that it is 0 in the center, why does a black hole have a singularity in the center instead of 0 gravity?
No one thinks there is a singularity. That's just pop-science bullshit. What actually is there no one knows for definite.

>>16556758
>>16556764

Then is every depiction of the gravity well on top wrong?

>>16556788
No, because they are showing the gravitational potential energy and not the strength of gravity at some distance.

if everything is a wave, or at least behaves like a wave, doesn't that explain why opposing charges attract each other and the same charges repel?
an electric or magnetic charge is a wave of some frequency and amplitude where positive and negative wave phases differ by a 180. if two same charges are near each other then they create a constructive interference between them which increases the amplitude and consequently the potential energy between them. because they want to return to equilibrium, they will move away in the exact opposite directions where the energy is at its lowest. likewise opposing charges will experience destructive interference so the lowest energy state is between them and causes them to attract

>>16556745
>Everyone explains the gravity in the exact center as being 0 because there is an equal amount of mass pulling you from all directions.
is there something you dont understand about that explanation?
>If you insist that it is 0 in the center, why does a black hole have a singularity in the center instead of 0 gravity?
technically it is zero in the center. when the black hole is to your right it pulls you rightward, when its to your left it pulls to leftward. if you crossed the center, theoretically at some point it must stop pulling you.
>>16556764
anon always tried to convince everyone that he didnt make this post with seven cocks split between his ass and mouth, but the reality is we just dont know for sure.

I have an old AM/FM radio and equally old crappy feature phone. Why do I hear weird noises in the radio whenever phone connects to a base transceiver station?

Bitcoin supply graph resembles an exponential function similar to charging a capacitor or a terminal velocity, Max(1-e^-x) but not quite. Is that because halving the reward makes the exponent to be a power of 2, and it is also discreet, not continuous similar to how a geometric progression is a discreet equivalent of an exponential function? How should the bitcoin supply formula be changed to have the exact exponential shape Max(1-e^-x)?

>>16556803
no

>>16557701
because?

>>16557705
because
1. its stupid
2. read a book
3. the minimal energy state would be in a trough
4. its stupid

>>16557715
i know for a fact that you wouldn't accept such an answer if it was me who wrote it

>>16557685
It shouldn't. But to get there you have to modify your τ, but that should be a real world factor anyways. A good τ will be on a long enough term to make no-coiners seeth and diamonds hands rich and bagholders late.
Amen.

>>16557685
>Bitcoin supply graph resembles an exponential function similar to charging a capacitor
you see exponentials everywhere because theyre the solution to the most basic differential equation you can write:
[math]\displaystyle f'=\alpha f[/math]
in other words, the rate of change of a value is proportional to value itself. its a relationship that shows up everywhere. for example:
>the rate that water flows from a tank with a hole in the bottom is proportional to the amount of water in the tank (more water = more pressure at the bottom)
>the rate that voltage changes on a capacitor is proportional to how much current it can drive through a resistor, which increases with voltage, therefore a capacitor will discharge quickly at first, then slowly decrease
for the bitcoin graph, assuming nothing else is going on (i have no clue how the bitcoin supply works, if its capped/controlled, etc), you could say that the incentive for mining bitcoin decreases with the addition of new supply.
>How should the bitcoin supply formula be changed to have the exact exponential shape Max(1-e^-x)?
what is the bitcoin supply formula?

>>16557759
If I asked something stupid and somebody told me to read a book I'd read a fucking book

>>16557822
nigger answer
provide a counterexample or gtfo

>>16556803
This is all complete nonsense. Out of phase waves cancel, resulting in a constant zero amplitude everywhere in both space and time. There is no way to make the a repelling force that matches with the forces of nature.

>>16557864
>Out of phase waves cancel
yes
>resulting in a constant zero amplitude
yes
>everywhere in both space and time
why everywhere? there's nothing else around (in this example). the only interaction can happen between them

>>16557927
So how does zero amplitude everywhere produce an inverse square law?

>>16557936
>>16557936
no, no. you're saying everywhere. i'm saying that it happens only between them. in every other direction they're just vibing into distance, unaffected
inverse square law also works here. the interference is the strongest at the smallest distance between the charges which is a straight line between them

>>16557957
Are you high or just lack an education?

>>16557961
look
the blue arrows represent waves that just propagate wherever at their own frequencies and amplitudes. red arrows are where the waves meet and destroy each other, creating a sort of lower potential or a "hole" that "hole" is the deepest at the shortest distance between the charges, that's where they cancel each other the strongest. charges want to be in the lowest possible energy state so they move towards each other
yes, i made them balls but it works with a wavefunction just the same. it's more convenient to draw it like that

>>16557978
i think the biggest issue with your theory is that, by definition, waves consider time and space to be interchangeable. when you say a negative charge is 180 degrees out of phase from a positive charge, thats identical to saying the charges are in-phase and located half a wavelength away from each other (or one and a half, or two and a half, etc). and obviously moving a charge doesnt change its sign. if i have a positive charge thats being attracted to a negative charge some distance away, can i move the negative charge a little closer/farther away and get them to repel each other? your theory would postulate that moving the negative charge and replacing it with a positive charge would be identical from the from perspective of the positive charge,

>>16557996
i do say wave and phase but i don't mean it in literal sense. more like, they exist in their own positive and negative spaces or fields
imagine two parallel and intersecting planes (or just go straight into 3D space) where positive and negative charges are sort of upward and downward spikes. these planes are distinct but interact with each other. now two charges a "hill" and a "hole" meet and they happily move towards each other into a lower energy state but can not fully cancel each other because they remain in their respective fields, creating a dipole

How the fuck do I make a chi square out of this?
Am I stupid or is there just not enough data?

>>16558061
It is more like when you tie a knot. The knot can only get so tight because of the physics of the rope. Positive / negative reference and the lines that are supposed is a higher dimensional tension.

>>16557814
[math]\sum_{i=0}^{32} 210000 \times \left( \frac{50}{2^i} \right)[/math]

>>16558071
It would only have 1 degree of freedom, but you could do it. I'm guessing the question wants you to test whether a uniform distribution fits the data?

>>16558173
Nope, it wants me to use that to solve a chi square and figure out if i would use a goodness of fit or test of independence

>>16558184
>solve a chi square and figure out if i would use a goodness of fit or test of independence

I'm not sure what exactly you mean by this. Could you post a picture of the whole question?

>>16558189
full dataset

>>16558189
full question

>>16558197
>>16558199
Yeah it seems to me like they just want you to use the data to determine whether the two different reinforcement mechanisms show a significant difference in efficacy. This would just be a test using expected frequencies of 22, with 1 degree of freedom.

>>16558208
I appreciate the help but I already gave up and turned in some garbage using those numbers. 2 calculators gave me two different answers as well. I'm just too stupid for this

>>16558061
> i do say wave and phase but i don't mean it in literal sense
that's okay, science is completely fine with vagaries and words that don't mean what they really mean. precision and rigour are for other people.

Any online transcription jobs that are hiring? I've seen several that have waitlists or no hires unless you have years of experience.

can anyone here tell at a glance whether or not the two equations circled as be expressed as a matrix equation like
[math] \displaystyle
\begin{bmatrix}
a_0 & a_1 \\
a_2 & a_3
\end{bmatrix}
\begin{bmatrix}
D_{max} \\
D_{min}
\end{bmatrix}
=
\begin{bmatrix}
R_1 \\
R_2
\end{bmatrix}
[/math]
i dont feel like doing algebra right now and chatgpt is having a rough of it

>>16558317
before anyone replies to this, yes i see it has no solution now

>>16558302
1. Are you from Nigeria/Kenya/India/some other former British colony in the third world?
2. Are you willing to work for less than $5/day?
If your answer to both is "yes", then there are plenty of companies who'd be willing to hire you.

How long until thorium reactors? Weren't they going to come out 10 years ago?

>>16558378
>Weren't they going to come out 10 years ago?
That was only said by people looking for funding. To develop a completely new and untested reactor technology would cost an amount no one is willing to invest. It is both cheaper in both time and money to simply optimize existing, proven tech.

>>16536751
>>16536971

It seems you are asking whether you can define a conjugate quantity to boosts of frame in the same way that momentum is conjugate to translations of space, energy is conjugate to translations of time, angular momentum is conjugate to rotations of space, and so on.

The answer is yes (it is related to the coordinates of the center of mass), but it is not a conserved quantity since the Hamiltonian is not invariant under boosts.

>>16558285
joke's on you because the entirety of quantum physics is about analogues because it's easier to do the maths

>>16557246
*dzzt, dt-dt-dt, dt-dt-dt*?
was pretty common in the flip phone era

How much redundancy in commercial aircraft?

>>16559268
iirc anything that is critical to flight is at least triple redundant. Specifics depend on the model of the plane.

>>16559273
i think you mean double. double redundant = two back-ups = three total.

>>16559273
What about shit in the actual jet

>>16534688
How does orange man's executive order "mean" all US citizens are female? Weren't we more like indeterminate until weeks later?

>>16559320
No, three total.
Triple redundant simply means all three do exactly the same thing.

https://ieeexplore.ieee.org/document/495891

>>16559521
It doesn't.
Liberals are insane.

>>16559550
Only the flight control is redundant? So the jet turbine isn’t ?

>>16559563
Planes have more than one engine anon.

>>16559566
Can you fly with just 1?

>>16559567
Yes. Even on a 4 jet passenger plane it can lose 3 and still land.

>>16559572
Not too shabby

>>16559550
thats super retarded nomenclature.
>triple redundant = three things
>double redundant = two things
>single redundant = one thing ???
unless the word redundant already implies the word double, so “single redundant” would be an oxymoron. still dumb tho, i would expect the prefix to indicate the number of acceptable failures.

>>16559567
FAA regulations say that any multiengine plane must still be able to climb with a single engine failure. dual engine planes can fly with only 1 engine. 3 engine planes would likely not be able to climb on 1 engine, and 4 engine planes would probably just be noisy gliders on 1 engine. thats part of the reason you don’t see too many 3 and 4 engine passenger aircrafts anymore; once we figured out how to build dual engine crafts that could fly over the pacific, there wasnt really any point in using more than 2 engines.
>>16559572
you can land on zero engines if youre brave enough.

>>16559652
Triple redundancy usually means that all three (or more) devices / circuits / whatever are active and running in parallel and then some sort of voting mechanism occurs so if at least two agree on a result that is what happens. Like in the flight computers, each are written separately by different companies so there is no shared code. If a bug exists in one, hopefully it doesn't in two or more.

How can I go about proving : [math] \lfloor{ \log_2(n+1)-1} \rfloor = \lfloor{ \log_2(n)} \rfloor [/math] ?

>>16559772
Normally I would say consider the cases
[math]2^k \leq n < 2^k - 1[/math] and [math]n = 2^k - 1[/math] for each integer [math]k[/math] but that equation is wrong so you can't prove it.

>>16559772
You can't, it's a false statement. If fails for all [math]n = 2^k[/math], where [math]k > 0[/math].

i got a fishbowl that's around ~6L in volume. how powerful of a halogen lamp would i need to get to keep it at 21~24 ºC, taking into account my room is 15 ºC on average?

Which of these is right?

>>16560136
The first. The angular velocity and rate of precession are constants.

>>16559803
Sorry, perhaps equality isn't the right way to refer to what I'm trying to prove. I essentially want to prove that if [math] \le 2^{d+1} -1[/math], then [math] \ge \lfloor \log_2{(n)} \rfloor [/math], where [math]n[/math] and [math]d[/math] are integers.

I was able to get to [math]\lfloor \log_2{(n+1)} - 1 \rfloor \le d[/math] using algebra, but am struggling to use that to show how [math]\lfloor \log_2{(n)} \rfloor \le d[/math]. Any advice on where to go next?

>>16560203
> I essentially want to prove that
What you wrote still doesn't make sense. Write it in full.

>>16560220
Sorry, there is the full problem:

If a binary tree with depth [math]d[/math] has at most [math] \le 2^{d+1} -1[/math]
nodes, show a binary tree with [math]n[/math] nodes has depth [math]\ge \lfloor \log_2{(n)} \rfloor [/math]. Given [math]d[/math] and [math]n[/math] are integers.

I started off with [math]n \le 2^{d+1} -1[/math]:

[math]n+1 \le 2^{d+1}[/math]
[math]\log_2{(n+1)} \le \log_2{(2^{d+1})}[/math]
[math]\log_2{(n+1)} \le d+1[/math]
[math]\log_2{(n+1)}-1 \le d[/math]

At this point, I would assume I need to floor both sides of the inequality: [math]\lfloor \log_2{(n+1)} - 1 \rfloor \le d[/math], but am a bit lost on what to do afterward to show [math]d \ge \lfloor \log_2{(n)} \rfloor [/math]

I'm in space, pushing on the top point of a wheel. I'm getting pushed back and moving right, torque is applied to the wheel so it's getting spun. Does the wheel move left?

If it doesn't, then left-right momentum wasn't conserved.

If it does, then I just created a spinning wheel moving left. But if I was lined up differently I could have applied the same force along the center of mass, created a non-spinning wheel moving left. The spinning wheel has more energy than the non-spinning wheel so didn't I just transfer different amounts of energy despite applying the same force for the same time over the same distance?

>>16560267
if the change in energy due to the force was truly the same then the spinning wheel would be moving slower, with less linear momentum. you would also have less linear momentum since the ball wouldnt be able resist your force as effectively, so linear momentum would be conserved.

>>16560287
>you would also have less linear momentum since the ball wouldnt be able resist your force as effectively
I don't understand what you mean by this. I've decided that I'm going to push exactly as hard no matter what. Maybe I'm shooting photons at the top of the wheel, since I understand that imparts momentum.

>>16534688
Does the existence of black holes destroy the Poincare theory, with solid experimental proofs?
Who can say universe does not have a structure of cheese with huge holes(black holes, and consequently is not a sphere?

>>16559652
>Triple Redundant = three things
>Double Redundant = two things
>Non redundant = one thing
I'm almost certain you're an H1B. Your grasp of language is very bad.

>>16560299
>I've decided that I'm going to push exactly as hard no matter what.
W = force x distance. you may be pushing the wheel just as hard, but the wheel isnt moving the same in both scenarios. moving the center of a wheel by some distance d requires moving the entire wheel by the same distance. but moving just the perimeter by a distance d doesnt necessarily requiring moving the center of the wheel at all. so if youre pushing the same in both scenarios then those are two different amounts of energy exerted.

>>16560337
>Triple = 3
>Double = 2
>Non = 0
oh yea bro that makes so much sense. why the fuck would i think single comes next? of course "redundant" and "double redundant" would mean the exact same thing.
kys faggot, im never using the word like that.

>>16560338
The center does move or it would sheer, unless there is a bearing or something.

>>16560354
i said doesnt *necessarily* require moving the center. in the described scenario you would need a bearing and therefore the center would move a little, but if you devised a way to spin the wheel without increasing your own linear momentum then the center wouldnt move. a reaction wheel, for example.
>>16560337
actually im not done. if i had 8 hard drives in a RAID6 array (meaning 2 of the drives failing is fine, but 3 results in data loss), how would you describe the redundancy of the array? there are 8 drives, so you would call that octuple redundant, right?

>>16560338
I may see what you're saying if I'm taking the atom at the top of the wheel, pushing it for a while in a slightly curved path, and then repeating for a new atom at the top of the wheel. But isn't pushing on a certain location on a wheel without needing to follow atoms around a common thing people do in mechanics? And isn't the accepted result that the center of mass will accelerate in the direction you're applying your constant force as if the force was applied to the center of mass?

Even if you are following atoms around for small amounts of time the direction of the force applied by me should mostly be the same so it seems like I should be moving very close to the same rate. So to preserve momentum the wheel's center of mass would have to be moving at almost the same rate as if I pushed there, whereas the increased angular moment is scaling directly with the force.

>>16560267
Let me restate things a bit. Pushing on the wheel is messy because of the direction of the normal force, so suppose instead you shoot a laser at the wheel, and the light is 100% absorbed. The laser has a constant power (energy per time) and imparts a constant force (momentum per time).

Since the laser has a constant power, if you shine the laser for equal amounts of time in both scenarios the wheel will have the same energy. The problem is that the spinning wheel has less translational velocity than the non spinning wheel, so it moves over less distance during the time in which you are applying a constant force, so apparently you have violated the work energy theorem.

The resolution is that you are not actually applying the constant force to the same particle in the first case. The work energy theorem is derived for point particles not rigid bodies. You can extend it to rigid bodies by including an extra energy term where the change in rotational energy equals the constant torque time the angular distance it rotated as you were applying the torque.

>>16560368
>And isn't the accepted result that the center of mass will accelerate in the direction you're applying your constant force as if the force was applied to the center of mass?
clearly not. when you push on the outer most part of a lever, does the fulcrum have to resist 100% of that force?

>>16560368
>And isn't the accepted result that the center of mass will accelerate in the direction you're applying your constant force as if the force was applied to the center of mass?
Yes. Ignore the other guy.

>>16560364
ah a reaction wheel is a good example. Nice way to abstract

greetings from diy

I’ve been working on a robot for a few weeks and there’s a question that doesn’t stop bothering me:

Given that the motors cannot change speed instantly (but are bound to acceleration times), is it even possible to move in, say, a perfect square?

Intuitively the corners will always be a problem (if both axes have zero speed, they can’t start up in just any xy direction) and I can’t find a single paper that takes this limitation into account. But on the other hand it seems I can move between any two points in a straight line (theoretically, I’m not at testing stage yet).

Of course I could just lift the Z axis whenever I reach a corner and then initiate a new line from another point but that feels inefficient

Also good terms for google searches are very welcome

>>16560396
>Given that the motors cannot change speed instantly (but are bound to acceleration times), is it even possible to move in, say, a perfect square?
This is what PID loops are for. They compensate for lags, sags, and overshoots in mechanical systems to give as clean and linear an operating behavior as possible.
The "squareness" of the square would be a function of your overshoot and settling times.

>>16560384
im sorry for calling you a faggot, it was rude and uncalled for.

>>16560396
they obviously could and it has nothing to do with acceleration. Imagine a robot on a rail, driven by rack and pinion. Its arm has two positions, high and low.
If the robot follows motion:
invert high/low
invert left/right
It could make a square given square distances are parameterized.

>>16560399
I know all about PID loops but don’t see how it would work in this case. If I’m at some (x,y) corner both motors have to stop. Then let’s say for a move in y+ direction I need to start with M1 at 3rpm and M2 at 1rpm. But in order to get there I need to start both of them (at say both 0.1rpm/s acceleration). There is no way I can keep them in exactly 3:1 all the time right? There’s no infinitely small acceleration in electric motors

>>16560406
That is easy because the axes of motion are equal to the directions of movement but maybe I am missing something.

>>16560383
>when you push on the outer most part of a lever, does the fulcrum have to resist 100% of that force?
I dunno, I've never pulled on levers with force meters in space before. But many sources on the internet seem to think so. At least if you push on both sides of a first degree lever the fulcrum has to counteract both forces.

>>16560377
>The problem is that the spinning wheel has less translational velocity than the non spinning wheel
But that violates conservation of momentum, unless my laser pointer is deciding how much to push me back based on what it hits.

>>16560430
>There is no way I can keep them in exactly 3:1 all the time right?
technically no, no matter how clever your solution is the error will never be zero. but that’s not very interesting.

>>16558317
I see you already got your answer, but if you want to know how to tell at a glance, matrices are part of LINEAR algebra - notice how the R's in your matrix equation is written as a LINEAR function of D's. The inverses of a linear function is also linear, which involves inverting matrix A to get A^{-1}.

If you want to barely think and know at a glance if it can be written as a matrix equation, ask yourself, does it look linear? (Yours do not).

A lot of the value in matrices is that lots of problems can be turned into a linear problem, like how you can taylor expand functions to a first order linear approximation, and if you can turn it linear, you can use matrices and computers to get accurate af answers.

if it's well conditioned, well defined, etc* >>16560500

>>16560430
Define "exact." You need to know what your tolerances are. If you're making a drawbot, I'd start with maybe 500um
>There’s no infinitely small acceleration in electric motors
You should be able to PWM them or something

>>16560259
Since n,d and the floor function all give you integers you can do:

[math]
2^{d+1} -1 \ge n \\
2^{d+1} \gt n \\
\log_2(2^{d+1}) \gt \log_2(n) \\
d+1 \gt \log_2(n) \\
d+1 \gt \lfloor \log_2(n) \rfloor \\
d \ge \lfloor \log_2(n) \rfloor \\
[/math]