/sci/ - Science & Math

[Physics Guy No.2711588]

Taking physis questions (if they arent too fucking retarded).

Any takers?

[Anonymous No.2711595]

what's the toughest problem in physics right now?

[Anonymous No.2711599]

Why is gravity the weakest force?

[Anonymous No.2711610]

Exactly how do I predict the orbit of the moon?

i.e how do predict where it is at a given day of the month?

Perhaps a stupid question. Physicsnoob here.. Go easy on me.

[Anonymous No.2711611]

Is there a way to solve the harmonic oscillator using path integrals without going through a functional determinant?

[Anonymous No.2711615]

do you believe in m theory?

[Anonymous No.2711638]

>>2711615
it's math

[Anonymous No.2711645]

>>2711599
Cuz if it weren't your mom would create a singularity.

[Anonymous No.2711669]

>>2711588
How can naked singularity have mass and no volume but no event horizon?

[Anonymous No.2711697]

okay everyone move on
The OP is a obviously a faggot who doesn't shit about physics

[Anonymous No.2711705]

What's this crap about energy having two states, off and on. With on energy being in our universe and off entering externally?

Or is this total shite?

[Anonymous No.2711709]

>>2711669
easy actually. if you have for example two parameters, linke here

http://en.wikipedia.org/wiki/Reissner%E2%80%93Nordstr%C3%B6m_metric

quote:
"These concentric event horizons become degenerate for 2rQ = rs which corresponds to an extremal black hole. Black holes with 2rQ > rs are believed not to exist in nature because they would contain a naked singularity; their appearance would contradict Roger Penrose's cosmic censorship hypothesis which is generally believed to be true. Theories with supersymmetry usually guarantee that such "superextremal" black holes can't exist."

then you can badly tune them to create one.
I discovered it myself in a calculation once, then I figured out what all the fuzz was about.

[Anonymous No.2711712]

>>2711697
You haven't been here too long have you?

[Anonymous No.2711714]

How happens when an alpha particle collides with beta particles?

do they cancel each other out and form a helium atom?

[M00T !!NrZfbTXaBN3 No.2711718]

Does an atom remain at a state of probability if it is cooled down to absolute zero?

[Physics Guy No.2711719]

>>2711595
Merging Quantum Field theory with General Relitivity.

[Anonymous No.2711722]

>>2711697
ha, this one
got me slappin my knees

[Anonymous No.2711723]

Bernoulli!
A liquid (p=1.65 g/cm^3) flows through 2 horizontal sections of tubing joined end to end. In the 1st section the cross-sectional area is 10 cm^2, the flow speed is 275 cm/s, and the pressure is 1.2x10^5 Pa. In the 2nd section the cross-sectional area is 2.5cm^2. Calculate the smaller section's flow speed and pressure.

I'm just confused because I didn't use the given pressure at all. Well you said you were taking physics questions...

[Anonymous No.2711725]

>>2711705
never heard of this before, is this related to string theory? like that the energy is part of propagation in other dimensions

[Anonymous No.2711743]

More math related [Im guessing you know your math though], but how would you rite out an equasion to demonstrate infinaty? I was thinking about x+1=x [an ever increasing line] but that doesnt help for curves [for example: 1+1+2+3+5+8 ect. (cant remeber what that patterns called)].
Sorry for the rambling, its jsut been bugging me for the last few days.

[Anonymous No.2711745]

how exactly would they cancel out?

[Physics Guy No.2711746]

>>2711610
Well I'm sure there are some basic astro approximations that you can just use. Pick up a basic college into to astro book, and look.

The actual way to derive that shit (in first order), is the "two body problem". You need to know lagragian mech, and cals, to do it though.

[Anonymous No.2711753]

>>2711718
you must first say what Temperature means in this context. there's no ideal gas, so this way of viewing it is out of the question. the most abstract definition, via entropy, is problematic for just one particle with fixed energy. too view parameters.

[Physics Guy No.2711754]

>>2711611
What harmonic ossilator? In what context?

[Anonymous No.2711758]

>>2711725
Nah, reasonably comfortable with my (biologists) understanding of string theory and this wasn't it.

It all branched from some arse on my minecraft server banging on about how he does physics at university and this is cutting edge right now. Personally I'm beginning to think the guy was just lying and trying to impress the 14yo who thought he was a big deal - but there's still something niggling away about it...

[Anonymous No.2711760]

>>2711746

Thanks man.

[Anonymous No.2711762]

what's the mass of an object going faster than the speed of light?

[Physics Guy No.2711775]

>>2711615
It is a nice math. But it is only a math. Until M-theory makes some actual testable prediction, it is not considered science.

[Anonymous No.2711776]

>>2711762
in the real world zero because its a photon. but i think infinite was the answer you were looking for.

[Anonymous No.2711785]

So, hmmm...., tell me about this dark matter. Any evidence besides some missing matter?

Are there any alternative theories you know of, like a revised theory of gravity?

[Anonymous No.2711789]

What is the difference between Nuclear Fission and Nuclear Fusion?
Which is better?

[Anonymous No.2711790]

>>2711776
photons do not travel faster than the speed of light

[Anonymous No.2711795]

>>2711743
Sorry for the spelling, I forgot to spell check

[Anonymous No.2711797]

>>2711789

Fission is breaking an atom up into smaller pieces
Fusion is combining atoms into bigger atoms.
Fusion would be much better if we could fucking use it.

[Anonymous No.2711798]

hit up this thread for two
>>2711488
>>2711488
>>2711488

[Anonymous No.2711799]

>>2711719
Do you think the person who figures that out will be worthy of a Nobel Prize?

[Anonymous No.2711802]

why do you need killing vectors for symmetries in the noeter theorem.
say you have a flow which isn't a symmetrie of some spacetime g - why shouldn't an action S still be invariant?

[Anonymous No.2711803]

Hm. OK. Say, where does the energy gravity imparts on matter come from? It seems like "it's free".

/sounding like a retard

[Anonymous No.2711816]

>>2711799
certainly.
But in this day and age, the chances of one person finding out are small.

[Physics Guy No.2711823]

>>2711762
Nowadays Mass is general stated in terms of "rest mass". The mass of the object if it were at "rest".

The idea of defining a "realtisic mass" that depends on the velocity of the object is outdatated, and isnt used in the physics community.

Hence, whenever we talk of mass, we mean rest mass. And rest mass of an object does not depend upon its velocity.

[Anonymous No.2711824]

>>2711754
The context is irrelevant, the harmonic oscillator is pretty well defined. I don't think you even understood the question.

[Anonymous No.2711830]

>>2711803
>the energy gravity imparts on matter
?
>>2711743
what is the question here

[Anonymous No.2711846]

Suppose artificial gravity were possible and implemented on an interstellar ship in such a way that the people on the ship experience 1G.
What effect would this mobile gravitation field create on the solar system, given that any gravitational field extends much farther than the object producing it. How could these effects be overcome?

[Anonymous No.2711849]

>>2711824
If the context is irrelevant, so say you take QM, then the model is analytically solvable and the path integral formulism should arrive at the same solution without any troublesome heat kernel calculation.
I mean that's my guess. How do you come about the question?

[Anonymous No.2711854]

>>2711816
Why is it different in this day and age? Certainly it's easier with the wide availability of knowledge and books (in 1st world countries, the only places where you would even give a shit about this stuff anyway).

[Anonymous No.2711855]

>>2711846
that would be entirely dependent on the technology used to create the artificial gravity

[Physics Guy No.2711866]

>>2711824
The harmoic ossilator is just an equation. In just about every branch of physics you will get somthing called the "harmonic ossilator".

You speak of functional determinate and path integrals, which is used in QFT. However, when the fuck are you encoutering a harmoinc ossilator in QFT? What kinda pertabation theory are you using? What order? What are you calculating?

I can't say I recall a harmonic ossilator in QFT, but I could be wrong.

In anycase, All QFT can actually be done without fucntional determinates. In fact when I first learned that shit, I didnt use them. In fact, many QFT Books dont use them at all.

[Anonymous No.2711875]

In the fukushima reactor, explosions are thought to have been caused by a build up of hydrogen. How did the hydrogen get there, when all the reactors contain is boric acid and water?

[Anonymous No.2711888]

>>2711846
Since this is a purely hypothetical question this answer might be as useless as the question, but I would suggest that, instead of having the machine accelerating you at 1G all the time, you should just accelerate once and then travel in the vacuum of space at constant speed.
The effect outside would be just for a short time and of course fall off at about 1/r²

[Anonymous No.2711890]

>>2711849
I'm looking for a way of solving the harmonic oscillator using path integrals but without going through the generic kernel determinant stuff. I know there is one but I've lost the reference.

[Anonymous No.2711895]

can there ever exist an object in our universe that is truly "unbreakable". like im talking about nothing in our universe could bend/disfigure it. And if so. what would happen if you threw in in a black hole, or even each half in its own black hole

[Anonymous No.2711899]

>>2711875

how is the chemical name for water? what happens if a lot of energy in form of heat gets induced?
think about it.

[Anonymous No.2711902]

>>2711875
>water
>where did the hydrogen come from?
>water

[Anonymous No.2711903]

>>2711895
>perfect shield vs. the perfect sword

[Anonymous No.2711921]

If a tree falls in the forest and no one is around to hear it, what colour are its leaves

[Physics Guy No.2711922]

>>2711743
There are many different types of "infinities" and concpets about infinity. You need to figure out whcih one you are trying to talk about.

In any case, there is already tons of math on this shit.

Looks up the work by George Cantor.
http://en.wikipedia.org/wiki/Aleph_number

Im sure there is other works too, you just gotta look around.

[Anonymous No.2711937]

>>2711921
The same color they where before the tree fell assuming all other variables remain constant.

[Anonymous No.2711956]

>>2711899
>>2711902
but why does it split? why doesn't water split in steam explosions?

[Anonymous No.2711964]

>>2711895
If you model something using fundamental strings, you can't cut a closed string

>>2711854
because sience is an industry and the geniuses are boght by IBM and the Nasa. Also, experimental results are often optaint in companies, say apple producing tough screen, and then these people don't become famous as persons.
It's not impossible that one guy discovers something really really big, but it's not as likely as in the 20's

[Anonymous No.2711969]

this may indeed be pretty fucking retarded but damnit im asking anyway.

in terms of just normal greenhouses, why dont they use one-way mirrors instead of windows to let the light in and then bounce it around, instead of letting it in and then letting it go right back out?

[Anonymous No.2711974]

>>2711866
You didn't answer my question. Instead you revealed that you never listed to more than QFT I. Or a graduate statistical mechanics course for that matter.

[Anonymous No.2711992]

The total force F exerted on the top of the mast at B
by the forestay AB and backstay BC has components
Fx = 180N and Fy = -820N. What are the magnitudes
of the forces exerted at B by the cables AB and BC
respectively

[Anonymous No.2712000]

>>2711992
This seems really easy
If you draw it I could probably do it and I'm just a high schooler

[Physics Guy No.2712002]

>>2711875

Case 1)

Protons are produced.
All you need are protons, and (maybe, depending on definition) electrons (which are everywhere) to produce hydrogen atom. Hydrogen atoms come together to form H2 (hydogen gas).

Case 2)
H20 is broken, producing excess hydogen atoms, which will bind together creating hydogen gas.

I am thinking case 2) happens alot more then Case 1)

[Physics Guy No.2712023]

>>2711974
Yeah, I did. I said you can do all QFT without fucntional determinates. You are a funny guy.

[Anonymous No.2712031]

>>2712000
I just dont get how to do this shit.

I understand that I have to find the force components then simultaneously solve but somethings just not clicking.

diagram attached

[Anonymous No.2712050]

>>2712002
two sounds more likely, but I still don't understand the water breaking thing. Why isn't it forming a superdense vapour or just becoming increasingly pressurised? isn't the H2O>>>H2 +O transition exothermic?

[Anonymous No.2712060]

Whoah, how can you talk about rest mass if said object is on a fucking rock in space, moving 300 km/s ?

[Anonymous No.2712071]

>>2712060
because velocety is relative, bro

[Anonymous No.2712075]

>>2712060
Rest is relative.

[Anonymous No.2712077]

Draw it out diagrammatically. Sooner or later you'll learn it.

[Physics Guy No.2712078]

>>2711846
The equivalnet princple in General relitivity says that a graviatational field is equivalent to acceleration (for the sake of your purposes).

Hence If I have an "accelerating rocket" I generate somthing that appears like a "gravitational field" in that rocket. The earth will feel no (negligible) effects from said rocket.

[Anonymous No.2712087]

what is the relative weights of oxygen compared to nitrogen at "normal" sea level/atmospheric conditions?
,,,,,,
that is, i already have found that oxygen is heavier, but how much? 1.1x, 1.5x. 1.00001x?

(srry, might be chem)

[Anonymous No.2712124]

>>2711723
The first part of the question can be solved by mass conservation. Assuming <span class="math">\rho_1 = \rho_2[/spoiler], this yields <span class="math">A_1 v_1 = A_2 v_2[/spoiler], of which you have A1, v1, A2.

The second part requires you to use Bernoulli's, and I'm puzzled how you found the pressure at point two without using the pressure given, as Bernoulli's states:
<div class="math">\frac{v^2}{2} + gz + \frac{p}{\rho} = c.</div>

Of course, you have all known information, so long as you assume the pipe is horizontal, we're looking at a streamline, blah blah blah.

[Physics Guy No.2712132]

>>2712060

Case 1)
You set up a frame that is moving with the rocket, and then the obejct will be at rest relative to the obejct" you then take mass measurements.

Case 2)
If you know what the object is composed of, the percentages of each, and the rest mass of those substances. You can just do a basic calulation on what the rest mass of the obejct is (regardless of what frame you are in).

The rest mass is used as an intrensic parameter to define a substance.

[Anonymous No.2712146]

why do heavier object need more force to accelerate to a given speed?
i get the feeling that mass anchors it into space
if this is so how does it happen?

[Anonymous No.2712148]

well I am sure someone will think this is too retarded but I think it makes sense.

I think of matter and antimatter as a number line, matter being positive and antimatter being negative. is it possible that there is another thing, the equivalent of i that is neither antimatter nor matter?

[Physics Guy No.2712152]

>>2712132
Case 3)
Knowing the objects relative velocity and acceleration to me, I can calcuate its rest mass directly (from that infomation)

[Anonymous No.2712159]

>>2712148
You think of matter and antimatter wrong, then.

[Anonymous No.2712166]

>>2712146

because a=F/m in Newtons equation

also:
http://www.youtube.com/watch?v=HgAQV05fPEk

[Anonymous No.2712178]

If the principle of relativity says the formulas of physics must be invariant under all smooth coordinate transformations, and the noether theorem says that a symmetry gives you a constant of motion - why don't you have infinite constants of motion?

[Anonymous No.2712180]

>>2712146
It's just like, a fundamental rule of physics, man
It's like asking why like charges repel

[Anonymous No.2712198]

what did they find in LHC?
've heard they now know if the higgs boson exists or not. 'ny idea?

[Anonymous No.2712211]

>>2712159
how so?

if I have 1 mol anti-helium and 1 mol helium and I mix them I get 0 mol

its like adding 1 and -1, I don't see any difference.

[Anonymous No.2712226]

>>2712148
Yes. Regular matter is charged in a certain way, antimatter is charged in the opposite way. Positive numbers have a certain distance from 0, negative numbers have the opposite distance. Imaginary numbers have distance from 0 in a different plane. Other matter has charge in a different way. One example of a different charge is gravity.

[Anonymous No.2712236]

>>2712180
but charges repel because of virtual photon interaction - QED

because they bend the electromagentic field like gravity - Classical View

[Anonymous No.2712245]

>>2712211
No, you get 0 moles AND gamma radiation.

This is not 0 moles.

[Anonymous No.2712252]

>>2712245
oh I forgot you get energy, yea mon good point.

[Physics Guy No.2712282]

>>2712148
It's a good question, don't feel embarrsed. The important part is that you are thinking about shit.

It is "possible" is suppose, but we have no evidence to justify such, so it isnt a valid train of scientific reasoning (so far).

The reason we have anti-particles ends up being cause qunatum mechanically we can have things traveling backwards (time reverse refernece frames). For every particle we see going forwards in time, we need a correspoding partcile going backwards in time, in order for the universe to be consistent.

An anti-particle though, essentailly has all the properties of regular particles. So they really arent that special (if you look at them from just a single time-forward frame).

[Physics Guy No.2712312]

>>2712226
That's some wild postulation bro. And there is no evidence or science to behind what you say.

It is intersting to think about, but all you are doing is math and phil (not physics).

[Physics Guy No.2712343]

>>2712148
Antimatter doesnt have negative mass.

There are tons of partciles that are there own anti-particle. Like the photon. It is both matter and antimatter.

[Anonymous No.2712354]

>>2712282
how can baryon numbers be violated then if the balance is inherent? I thought the existence and prevalence of one type of matter over the other was basically a coin-flip directly after the big bang.

it seems like chirality in the formation of molecules, if even 51% of the system is chiral one way it will organize and produce more of that isomer than the other.

[Anonymous No.2712368]

>>2712343
I never said it had negative mass, I may have implied that but I know it doesn't.

what the hell would negative mass look like anyway? it would just cause a shift in what we call zero mass.

[Anonymous No.2712407]

>>2712312
No, I was trying to demonstrate to him that the analogy has a direct, but shitty, conclusion. He proposed some kind of a third matter, and I was just saying that this sort of third matter would just be matter which experiences charges other than electromagnetism (and there is plenty of this matter).

I wasn't really postulating anything. There's absolutely nothing I said which would hint at some kind of guess about the way things are.

[Anonymous No.2712455]

>>2711922
Thanks OP.

[Anonymous No.2712529]

√(Chicken&nig)

[Physics Guy No.2712547]

>>2712407
Ic, ok. Sorry. Although, I don't think your analogy worked as desired.

>other then electromagntism

That is not the logical conclusion though. In your "thought experiment", the logical conslusion is for a type of matter that has "imaginary charge".

If the logical conclusion was to have another property, then we could just pick say "spin", or "parity", or "hypercharge" or "blah". We could have a "spin vs charge" plot, which actually is fucking doable. We can actually make such plots, and we actually find them useful at times.

[Physics Guy No.2712628]

>>2712354
I never said the "balance was inherit". I said the existance of anti-partciles is "nessicated" because of the inherit laws of QM.

Bascially, this means, that for every partcile, there must exist an aint-partcile. There cannot be a case where a particle does not have an anit-partcile. If I discover a new partcile, I have actually discovered two new partciles...lol. The other must exist.

It doesnt say anything about the inherit concentrations of the particles. The inhert concentraions of anti-matter as opposed to matter, will end up shining light on some fundmental question regarding the flow of time. If mass and antimass are not balanced, then I get a prefered refrence frame with respect to the flow of time.

[Anonymous No.2712748]

Say you are at the magnetic south pole with 2 pretty strong magnets with the same mass and you weigh them, one with its south pole pointing towards the earth and the other with its north.
If the magnets are strong enough, will they have different weight on the scale?
im thinking magnet with south facing down would be lighter.

[Anonymous No.2712764]

When a metal rod of length l is tied by a massless string on each end to a surface, and the string on one end is cut, why does the Ft go down for a split moment before the rod falls? (true situation)

[Anonymous No.2713056]

I'll throw /sci/ a curve ball

if time is not a vector quantity then does that mean there can never be a negative time (past) same thing also applies to the existence of a possible negative mass?

[Anonymous No.2713131]

>>2712368
I would imagine negative mass would gravitationally repell

[Anonymous No.2713159]

>>2712628
>Bascially, this means, that for every partcile, there must exist an aint-partcile. There cannot be a case where a particle does not have an anit-partcile. If I discover a new partcile, I have actually discovered two new partciles...lol. The other must exist.

Is this a view of supersymmetry?

Isn't the LHC's preliminary data analysis putting a constraint on the predictive power of supersymmetry in terms of the mass of the higgs boson?

[Physics Guy No.2713192]

>>2713159
>Is this a view of supersymmetry?

Nope, all I am talking about is basic relativistic quantum mechanics (special relitivity). Very simple shit. No super-symmetery required. I am not talking about super-symmetery.

[Physics Guy No.2713238]

>>2713056
The vector quantity you talk about, specifies an obeject has mutiple componets. Time, and mass are not vectors, as they only have once component. This has nothing at all to do with the value of a scalar time, or mass.

You are just throughing out unrelated concepts. Try harder.

[Anonymous No.2713658]

I actually went to see the Bates linear Accelerator today at MIT in Middleton, MA. You can google it and find it.

It was AMAZING. A MASSIVE underground complex of HUGE magnets and amazing machinery. It was by far the most insane crazy fucking awesome piece of engineering I have ever seen, and to think its 40 YEARS OLD!!!! I can't even imagine what the LHC looks like.

Seeing science like that makes me wet, and I want to live in the basement and work on that thing forever. So cool....

Anyway, I love Oppenheimer and Feynmann.

I was wondering today though...I saw dipole magnets the size of small cars. Why when you are working with an electron beam which is TINY you need magnets that are THAT huge?

I've put a fridge magnet against an electron tube and you can get it to curve dramatically, why the need for such huge magnets? A homogenous field?

[Anonymous No.2714230]

>>2713658
Bending isn't that hard to do. The Big Magnets are usually needed to accelerate the beams. You need big magnetic fields for that shit, as you are trying to accelerate massive particles near the speed on light.