Connection Definition and 498 Threads

When Fizeau (and Michelson and Morley) measured the fringe shifts that occur when light travels through a moving medium, how exactly (in words) did they deduce the change in velocity? My understand is this: 1) Count the fringe shifts that occur. 2) Calculate what the frequency shift must have...

First of all. We must not have any a priori or preconceived notions of what is reality but instead follow the evidence of what is the true structure (if there is) of reality. The Dirac Equation is one way to start. It predicts spins of particles and antimatter. How come the mathematics of it...

I would like to know if the following correct. Suppose I start with a connection on a real vector bundle and extend it to the complexification of the bundle. The curvature forms of the complexification seem to be the same as curvature 2 forms of the real bundle. From this it seems that the...

Could anyone please, explain the connection between the Free Energy and the Action? I know the definitions of each but not sure about the connection. I read somewhere that the free energy is the same as the action when calculated "on-shell". What does this "on-shell" thing mean in this...

Does the resistances of each phase in a 3 phase generator add together in the Star (wye)? I read on a windmill site that the Delta connection is typically one third the resistance of the Star. So if i had 3 phases that were .5 ohms each in Delta configuration, would the resistance be 1.5 ohms...

I've been having trouble connecting to this site for a long time, but recently, it has been almost impossible. I get both connection timeouts and extremely slow loads. I was wondering if anyone else is having trouble or if I need to hound my ISP. Thanks.

I am helping out with the installation of an alarm system and need some info regarding earthing of low voltage transformer lead. The alarm system has a 3 wire 12 volt AC output power supply as well as a back up 12 volt DC battery which also contributes to the AC supply to the main ciricuit...

I am confused from a couple of diagrams I have about how to correctly wire 3 small transformers to form a delta wye connection. The transformers are labeled as Primary H1 H2, H1 H2, H1 H2 Secondary X2 X1, X2 X1, X2 X1 My question is in all the diagrams I have the Delta connections...

If i connect the positive terminal of a 5 volt battery to positive terminal of 10 volt battery and the negative terminals of both batteries are also connected without using any resistance or any other components in between what will happen to the two batteries?. Will the one with higher voltage...

Just got a new computer. Has nothing on it but XP. Plugged a network cable into it and into my router. The network port is directly into the back of my computer, not into an add-on slot or anything. System does not detect any hardware. It does nothing. Shouldn't it detect the network? If...

The ouput of common emitter transistor 1 is connected to input of common emitter transistor 2. Please explain about the input and ouput signal (ac). 1.Is there any amplification after the transistor 1? Normally the input is in uA, the output is in miliA 2.Is there any amplification after...

Hi I am trying to find out a way to connect a 3 core cable (armoured cable) to a 3-pin socket... what would be the best way to go about doing this ?? any help would be appreciated regards

hi there, how can i show that the lie brocket is not connection? Many thanks =)))

Hey guys, I'm following a course on vector calculus and I'm having some trouble connecting things. Suppose we have a three-dimensionale vectorfield F(x,y,z)=(F1,F2,F3) and suppose we have a potential phi for this. So: F=grad(phi). The field lines of a vector field are defined as d(r)/dt =...

What is the relationship between the quantum mechanical path integral and classical mechanics path integral?

The unusually cold weather in Europe must be related to the gulf stream which gives Europe its normally balmy temperatures as far north as the Arctic Circle in Norway. It was noticed this summer that the gulf stream had slowed down to almost a stop. Some scientists attributed this to the BP...

I cannot work out the following functional derivative: \frac{\delta}{\delta g_{\mu\nu}} \int d^4 x f^a_{\phantom{a}b} \nabla_a h^b Where f is a tensor density f= \sqrt{\det g} \tilde{f} ( \tilde{f} is an ordinary tensor) and should be consider as independent of g. In my opinion this is not...

Okay, so I'm trying to connect my TI-89 to my computer (I run windows 7 by the way) so I can put notefolio files on the calculator. I have the CD and usb that comes with the calculator, and used those to connect to the computer and download the TI connect software. This is where the...

1. Two masses are connected by a light string. The horizontal mass of 2 kilograms is being pulled to the left with a force of 30 Newtons along a frictionless surface. The vertical mass is 1 kilogram. What is the magnitude of the tension in the connection string? 2. Fnet=ma 3. My...

Hi. Could you please give me a description/analyse a variety of flux changes that can be used to produce an emf. Could you confirm what is flux and emf in this situation?

Do any of currently have or had some kind of emotional connection to commercial characters from your childhood (or adulthood)? For example, you buy Frosted Flakes because you feel emotionally "attached" to Tony the Tiger or you smoke Marlboro because you emotionally "connect" with the Marlboro...

Homework Statement A block with mass m = 5.00 kg slides down a surface inclined 36.9 degrees to the horizontal. The coefficient of kinetic friction is 0.25. A string attached to the block is wrapped around a flywheel on a fixed axis at O. The flywheel has mass 25.0 kg and moment of inertia...

Hi. I was wondering if anyone had ever done a relationship analysis of compression ratio in relationship to efficiency. I have heard that higher compression ratio can often relate to efficiency, but I was hoping to find some kind of graph correlation on it, however I haven't been able to find...

So I made this really simple circuit - a battery, some wires and a small light bulb. Now when I connected another light bulb with this light bulb, both of them where burning a tad dimmer than when there was only one lamp in the circuit. Why is that? The voltage and the amperage should stay the...

What is the relation between Hilbert Space and space-time? Are the two disjoint or is there something relating the two?

Homework Statement Two bulbs rated 25 W - 110 V and 100 W - 110 V are connected in series to a 230 V supply. What will happen? > > Homework Equations p = vi. p = v2/r The Attempt at a Solution I am not sure I know how to interpret it correctly. To find the current through...

Hi, Currently i am using Proteus 7.4SP3 to simulate the AD633 multiplier. The two input is a trend of pulses and i want to get the output. The problem is that it occur 2 warnings which is then stopped my simulation. 1. [SPICE] DELMIN increased to 1.11022e-016 due to lack of time precision...

As a freshman in college, I was wondering, is pi's connection with the very simple differential equation \frac{d^{2}y}{dx^{2}} = -y with initial condition that (0,0) be included (or even if that is not the case a connection can be made) the reason it is so ubiquitous in mathematics. This of...

Very quick question PLEASE - Star Connection! Homework Statement i'm just working on some questions on power engineering and there's a question on star connections. the wording is a bit funny - wondering if can get some clarification please. "a three phase load is composed of three...

i am now reading the PRL paper by simon on berry phase under adiabatic approximation, the wave function evolves as \langle \psi | d/dt | \psi \rangle=0. how to relate this equation to the connection on a fiber bundle? how to understand that the wave function is parallel transported?

Background: Math: An affine parameter provides a metric along a geodesic but not a metric of the space, for example between geodesics. A connection provides an affine parameter, and a non-trivial connection gives rise to Riemann curvature. Given the existence of a connection with Riemann...

http://prola.aps.org/abstract/PR/v58/i8/p716_1 I'm trying to read this, and it's not going very well! :frown: On the second page: What two numbers is Pauli talking about? Isn't a spinor of a particle usually characterized by a one number?

Just a quick question: I was wondering whether the Force Applied to a spring equates to the stress and whether the Displacement of a spring equates to the strain. I have been researching this on the internet and the units of stress are completely different to Force Applied and the same for...

Hi, all, According to my script, a connection \nabla_v is symmetric if the following holds (I assume for every pair of vectors): \nabla_v w - \nabla_w v =[v,w] What is the idea behind that? Why are we interested in that kind of symmetry (not for instance 0 instead of the commutator)...

Homework Statement Explain geometrically why the integral of dx/sqrt(x) for (x, 0,1)= [the integral of dx/x^2 for (x, 1, infinity)] + 1 Including graphs as well. Homework Equations The Attempt at a Solution I graphed both functions and they met at a point (1,1) but i don't really...

Hello everyone: I am trying to find a program or formula that will help me figure out how many windings, turns of coil, are needed per coil on a 6 coil steel stator ring powered by 3-phase AC power to get a certain magnetic field strength, about 1.3T. Is there any way that you could help me...

Hello everyone: I am trying to find a program or formula that will help me figure out how many windings, turns of coil, are needed per coil on a 6 coil steel stator ring powered by 3-phase AC power to get a certain magnetic field strength, about 1.3T. Is there any way that you could help me...

I just read a sentence in GRAVITATION by MTW (aka the "Princeton Phonebook") that made me realize a confusion wrt the metric, connection, and curvature. In short how are g_{\mu\nu}, \Gamma^{\alpha}_{\mu\nu}, and R^{\alpha}_{\beta\mu\nu} distinguished? They all include the description "how space...

On a low-voltage DC Solar system(up to 48V nominal), should I leave the lines floating or one should be grounded? I don't see any real advantage on any option...that's why I ask to confirm

So let's say for example there is a slide with two slits on it infront of a screen. A beam of electrons is aimed at it. A) What would happen to the size of the fringes on the screen if I decreased the spacing between the slits B) What would happen to the fringes if I moved the screen...

In a lot of textbooks on relativity the Levi-Civita connection is derived like this: V=V^ie_i dV=dV^ie_i+V^ide_i dV=\partial_jV^ie_idx^j+V^i \Gamma^{j}_{ir}e_j dx^r which after relabeling indices: dV=(\partial_jV^i+V^k \Gamma^{i}_{kj})e_i dx^j so that the covariant derivative is...

Now I'm just start to study the Kaluza-Klein theory from http://arxiv.org/abs/grqc/9805018. I try to calculate the Einstein Field equations in 5 dimensional vacuum space-time. we start with 5D metric tensor, \hat{g}_{AB}=\begin{pmatrix}...

I have a question about the nomenclature of the "spin connection". To me "spin" implies quantum mechanics. However, as I understand it, the spin connection is just a part of the covariant derivative of a vector that is written in tetrad (i.e., local frame) components. So isn't the "spin...

hi guys, I want to know if it is always possible to link two transformers in series with different rated voltage. And if there is any concern about the polarity. If it is not possible in which conditions it can be done?

Recently I've been doing some research in physics, and I've come across a problem: what exactly is the connection between General Relativity and gravitons? I know that General Relativity talks about the bending of spacetime and how that causes gravity, and that the graviton is supposedly the...

Hi! I just registered as I have been wondering quite a while about a specific question that grew in my head while reading about electronics in school. As I have learned voltage is a difference in potential. So if we have a 9V battery there is a difference of 9V between the two poles of the...

If the proposed Higgs field is a mechanism which "decelerates" certain particles (whereas not interacting with others), thus creating mass as we know it, would it follow from this that the field is also, ultimately, the source of gravity? If so, there seems to be a connection between gravity and...

Hi, I'm struggling to grasp the physical reason behind the fact that, in a curved spacetime, a change of metric implies, in general, a change of connection, i.e. if I have two metrics g_{ab} and \hat{g}_{ab}, in general \nabla_a \neq \hat{\nabla}_a. Besides this, is there any relationship...

Homework Statement If you were given an enclosed box, containing two 2000uF capacitors, which were either joined in series or in parallel, suggest, with a reason, how you would determine which way they were connected. Homework Equations C = C1 + C2 in parallel 1/C = 1/C1 + 1/C2 in...

Hello :smile: I am wondering about something. Why when I 'hover' over the windows connection icon in the system tray it is showing this: What does that speed mean? Because I am downloading something right now and it is certainly not downloading at 54.0 Mbps This is the actual...