Mystery — 395 discussions

In electrodynamics, the gauge potentials are not directly measureable, but components of the field strength tensors, which are the electric and magnetic fields are. But why are the electric and magnetic fields, the components of the curl of something not-measureable (the gauge fields)...

Homework Statement Homework Equations The Attempt at a Solution In part a, there is an important step, I don't know how to have the step that written in green colour. Does this technque have any name? Can you give me more example of it?

If cold air is more dense, why is higher altitude air colder and less dense?

i know this might be a dumb question but it was in my head and i would love to hear an answer, so the famous E=mc2..e obviously energy, m mass, c is the speed of light, but what speed of light? we all know that c is constant at vacuum but it changes when it goes through another medium like...

Hi Everyone! I am having a little trouble understanding the concept of drug chirality... I know what they are, but am unsure about how they are formed in the first place (is it a random chance that one enantinomer will be formed over the other, can the be specifically created...?). Also, how...

Hello again! Say I have a potential well, between 0 and a. I also know how the wave function looks like for (t=0): \psi(x,0)= \frac {2bx} {a} for 0<x<\frac {a} {2} and \psi(x,0)= 2b(1- \frac {x} {a} ) for \frac {a} {2} <x<a Now, I wish to find the wave function of a general time...

Lets say I have a negative line charge on a long thin rod, if I am at rest with respect to that rod I will see an E field. But If I am moving with respect to that rod I will see a B field. So why are people looking for magnetic monopoles, If B fields are E fields in disguise, wouldn't the...

I thought capacitance was a function of geometry. So how come when we put in a dielectric in between a parallel plate capacitor it increases the capacitance. Is this because we can increase the E field in between without worrying about dielectric breakdown. Or does it have something to do with...

Why is the de Broglie wavelength sometimes larger than the particle it describes? Thanks, Jake

In a spherical vessel with a hydrogen H2 and oxygen mixture O2 it is stated in a problem that we can derive that the concentration of oxygen [O2] can be derived to be: P / 3RT. With P the total pressure, R the gas constant en T temperature? How on Earth is this possible? I thought the...

"STEP" mission Does anybody know why http://einstein.stanford.edu/STEP/" was canceled, and if any similar one is planned for next years?

Hey, I took some photos of this part and they should be visible below or you'll need to click the attachments. But my question is as follows: I have no idea what to call this. I contacted Digi-Key and tried to describe it to them but to no avail. Notice, the pins are in 2x5 formation and...

Homework Statement I have a multichoice past exam that does not come with answers. Please help with the following: The binding energy of the X nucleus is 38.4MeV. Which of the following statements is FALSE? a) The binding energy of 38.4MeV represents the mass deficit between the...

Is it same as 'c'? or is it greater (though it may be very small difference) than the normal speed of light?

I recently fall upon this principle while trying to do this 3D mechanics exercise. http://img193.imageshack.us/img193/1416/legitwheel.jpg Looking from a side view (only z and y axes), this should be about right: http://img28.imageshack.us/img28/5758/momentsq.jpg Ignore the question marks...

A coworker has a well pump that is a 0.5 horsepower, brand new, no issues... He says the normal amp draw is 4 to 5 amps. This is puzzling because it is a 240V pump and the math works out to (746/240 = 3.1/2 = ) 1.55 amps. What is going on?

If there were no Space-Time before the Big Bang, then where did that explosion took placed?

Hi, I'm confused about something. Why is it that in magazines and videos it seems as though adding more transistors to a CPU will make it faster? Is it a numbers thing (like, instead of marking amps on signs, they show volts)? I mean, I understand that you can do multithreading, multiple...

Hi, I read sometimes that the gravity of Jupiter is enough to eject an asteroid or comet out of their orbit and fling them outside of the solar system. But gravity is an attractive force, how can it eject something? Thanks for any clarification.

what are fatigue cracks? what are the major sources of fatigue withing the fuselage? how can fatigue cracks be detected during inspection? how can the risk of fatigue cracks in the fuselage be reduced? why are they dangerous? what is their origin? I've tried to find answers for these...

This a question that has been haunting me for some time now. Regarding the rotational motion of rigid bodies why wasn't the moment of inertia defined as the integral sum elements of infinitesimal mass time the radius from the axis of rotation rather than the radius squared. In this case the...

Why are pseudo forces also sometimes called INERTIAL FORCES , even though their need arises because of non inertial frames??:confused:

Somehow it doesn't seem to me to be an S-shaped balloon with it's constant rotational speed. Any idea what this could be?

In classical physics, the two quantities that you need to know about a particle to describe it completely at an instant is x and p - position and momentum. Why is it that momentum is chosen as the second quantity - ie. couldn't we describe the particle equally well with x and v - position and...

So I'm working out on a potentials of the type x^2p, and I have a program that solves and gives the eigenenergies for a potential that I have (x^n in general). I noticed that for a ground state the potential x^4 has the smallest eigenvalue : 0.667981 in units where \hbar=m=\omega=1. I...

Homework Statement Hi guys In my book they use the following identity e^{ - i\widehat Ht/\hbar } = e^{ - i\widehat Tt/\hbar } e^{ - i\widehat Vt/\hbar } + O(t^2 ) where H = T+V, and the last term means "terms of order t2 or higher". I can't quite see how they reach this identity. First...

Is it 2 or 128?

Homework Statement How do you write Fe2S3 in IUPAC method, it would be great if you could explain and show some examples of IUPAC methods. The Attempt at a Solution I just want to see how you do one of them then I can probably get the rest, thanks a lot.

How is squareroot(x)*(1/x)= 1/square root x can somebody please explain this? I think I am having a brain lockup...

Dear Friends, I am presently studying physics on my own. (Not for a degree but just out of curiosity) My question is, both gravity and charge being fundamental forces, is science more comfortable in explaining one of them compared to other? I see some threads here wondering what exactly...

Why is Δsolubility / Δtemperature so much lower for NaCl than for other ionic compounds like KCl and NaNO3? (It's solubility curve is almost flat).

actually, there ıs a something I don't understand about the e value I could not figure it out this integral while solving for quantum physics, you will see the equation in figure. The problem is how We can make a solution about the e number while solving in integral.. Such as e power any...

Homework Statement My friend just sent me an answer to a problem he solved... But I am not understanding how d1 = L*x/h2 and d2=L*x/h1 How is that so? Homework Equations The Attempt at a Solution

Put a one rupee coin over a piece of card paper placed on an empty glass push the card with a sudden stroke of finger card will move ahead while the stone fall in glass, Why?

Who did and when, the first double-slit experiment using single electrons? (no wikipedia reference please...)

why does the moon keep rotating about its own axis? especially after so many comets have hit it?

Homework Statement 2/(tanx+cotx)=sinx Homework Equations Double Angle Identities, Pythagorean Identities The Attempt at a Solution 2/(tanx+cotx)= 2/[(sinx/cosx)+(cosx/sinx)]= 2/[((sinx)^2+(cosx)^2)/(sinxcosx)]= 2sinxcosx/[(sinx)^2+(cosx)^2]= 2sinxcosx = sin(2x) =/=...

Well, I've really been getting into Quantum Relativity and Quantum physics, and one thing really just seems fuzzy to me. Super Symmetry. Wikipedia goes into too much math and history and blah blah blah... Other sites just say the history of discovering super symmetry Some sites are...

Homework Statement You have paid big bucks to see Season of the Witch at the 3-D IMAX theater in Vancouver. Just before the movie is about to begin, the theater staff tell you that the lens for the projector has just broken! You really want to see the movie and decide that it should be simple...

Homework Statement Helium has the special property that its internal energy is directly proportional to its absolute temperature. Consider a flask of helium with a temperature of 20 C. If it is heated to twice its internal energy, what will its temperature be? 1. 293 C 2. 313 C 3. 40 C 4...

Homework Statement Fission reaction: 10n + 23592U --> 14156 + 9236 Kr + 3(10n) Why in the world is there a neutron on the left side of this rxn? Why not just reduce the number of neutrons on the right side to two?

Homework Statement Measurements show that a honeybee in active flight can acquire an electrostatic charge on the order of 90.9 pC. a)How many electrons much be transferred to produce this charge? Ne =5.67*10^8 b) Supposing two bees, both with this charge, are separated by a distance of 14 cm...

Average density of universe is 9.3 x 10^-27 Kg-mass/M3. Volume of Cubic-Light-Year is 2.7 x 10^25 M3. Result is .25 Kg-mass/CLY. If Dark Matter is 5 x ordinary matter then 1.25Kg-mass of Dark Matter per CLY. What if there was a billion times more Dark Matter in a galaxy than in the space between...

greetings, what is the meaning of a zero watt bulb?how can be any bulb glow without any power consumption? thanks

I am a bit confused by this observation. Every tensor is it's symmetric plus antisymmetric part. Thus for the components of a (0,3) tensor F_{\lambda\mu\nu}=F_{[\lambda\mu\nu]}+F_{\{\lambda\mu\nu\}} and if I write this down explicitly I end up that for the components of ANY (0,3)...

i know i haven't understood the concept of eddy current and that is why i am posting this question: why are EDDY CURRENTS circular?

Hi, has anyone else seen this news item http://www.physorg.com/news/2011-01-math-theories-reveal-nature.html on how to crack partition numbers using fractals? It came out on Thursday the 20th Jan 2011. They gave a tantalising glimpse and said the full new theory will be revealed on Fri 21 st...

Hi there. I'm a second-year physics student. I'm from Mexico (so please, forgive my english), and I'm on winter holidays. I've been studying Mechanics with the first volume of the "Course of Theoretical Physics", by Landau and Lifgarbagez, that awesome though hard book series. My study plan...

hi, i was just wanting to get a few opinions on where and maybe even when a black hole goes to. It's something I've read into a lot in the past few months; and I'm really interested to find out what others think. Thanks

Homework Statement I need help to decide if the series below are convergent or divergent. \sum_{k=2}^{\infy}(\frac{1}{ln(k!)}) Homework Equations The Attempt at a Solution I tried using the d'Alembert ratio test but the ratio is 1 if I calculated it correctly and then nothing can be said...