Behavior Definition and 317 Threads

Good morning everyone, I'm Giuliano and I would like to know how light behaves in a black hole and because it can not get out. More precisely, i understand that light moves in curved space-time format from the black hole, but once passed within swarzchild radius the photon is expected to impact...

If a gas is ionized using a sufficiently strong electric field (created by two plates, and where the gas is the medium in between), the positive ions would drift toward one plate while the electrons would be attracted to the other. What would happen when the electrons and ions reach the...

Hi friends..I am very confused with the magnetic behavior of a CT. CT secondary should never be left open.Okay I understand why. But how exactly does a shorted secondary cancel the primary flux? For that the primary and secondary currents must be 180 degrees out of phase while Lenz's law states...

My laptop has been driving me nuts for the past 28 hours. Weird things are happening when I try to use the mouse. For example, when I've just logged in (Windows 7), the mouse is always in one of these two modes: 1. Mouse actions work on the desktop, but not on the taskbar. 2. Mouse actions work...

i want to know the behavior of voltage in 11 KV underground and OH distribution line at different load conditions i.e. no load-full load ...

What will be the behavior of conductor at absolute 0 temperature?

So i have a question regarding the nature of the particle spectre at alice as a function of momentum. The spectre in question can be seen here. http://cerncourier.com/cws/article/cern/48325. My question is, why is it that the particle in the low momentum range are rising and the reaching a...

I have a barrel that collects rainwater from the gutters on my house. At the bottom of the barrel is a manual 'faucet' with a round handle for turning the flow on and off. On that spigot, I have installed a "Y" fitting. One side of the "Y" goes to the irrigation hose which I turn on when the...

The field lines inside of a solenoid all go in one direction, right? So why doesn't a magnet that's placed in the solenoid simply get forced one way or another. I tried this at home by placing a magnet in the solenoid(near the outside of the coil so that it stuck out a bit), and when I turned on...

Are there simple governing equations for FETs like there are for BJTs, and if so, what are they? For example, in the BJT case we have IC = β×IB IE + IC + IB I'm sure it depends on the type - MOSFET, JFET, etc. - so anything anyone could contribute would be helpful. From what I understand, the...

Hello everyone this is my first post here. I'm sorry if my spelling is terrible. I am no physicists so I would like to ask if my thinking was going in the right direction. When I say energy I really mean electromagnetic radiation. The Earth receives it constantly from the sun but there is no...

Hi, For an assignment at school I am looking into the behaviors of microwave propagation. For instance I have familiarized myself with Fraunhoffer diffraction (Single slit, Double slit and grating) and an amount of wave mechanics in general. What I would like to do however is to link all...

Hi all, I'm new here, and I hope I'm doing this right. I mean posting where I should. Feel free to let me know. ;-) First, I'm a biologist but I'm a scientist and I'm interested in magnets recently. I read that magnetic field attract oxygen liquid (all over you tube) and also gaseous since...

After working a homework assignment which required sketching effective potential energy for the gravitational/coloumb forces, I went and looked at a few effective potentials for inverse cube and inverse quartic (not sure if this is the right word; 1/r^4 force) forces, with inverse square and...

Homework Statement Griffiths Intro Quantum Mechanics free particle question. Normalize wave function, find Phi(k), Psi(x,t), and comment on its behavior for small and large a. The wave function given is Ae-a|x|Homework EquationsThe Attempt at a Solution I found the correct Phi(k), but for the...

I read that the top quark is "the smallest quark, which means it is the most massive". How can it be the smallest and yet the most massive?

Hello PF'ers, Why is it that two light-bulbs produce twice as much brightness as a single light-bulb would? If we restrict our attention to a single point in space where light from the two sources meet, the waves would cancel half of the time and reinforce half of the time, producing on...

Hello all, In the sketch attached below, I have a cylindrical coil with a cylindrical permanent magnet located in the center (assume the magnet can only move in the axial A-B direction). It is my understanding that if the coil had current flowing through it so that side A was the south pole...

Hi How to estimate the asymptotic behavior of this function? f(x)=\sum_{k=1}^{x}\log(k) I mean, a closed form function g(x) such that f(x)/g(x) tends to 1 as x goes to infinity.

In...... it has beenshown in an elementary way that is ... $\displaystyle\int_{0}^{\infty}\frac{\ln x}{x^{2}+a^{2}}\ dx = \frac{\pi\ \ln a}{2\ a}\ (1)$The integral (1) isvery useful to shed light on the behavior of the logarithm functionin the complex field. Let's suppose we want to solve the...

Hello all, I use an evaporation chamber at my lab every day. Basically, put some substance in the chamber, close it, bring it down to vacuum, and pump enough current through it to vaporize it where it deposits on a substrate. I've been using 175A to create a deposition rate of about 1...

We used to have a bird thread here a long time ago, but it went dormant - maybe it's time for a new one? I need help identifying a bird. It's thrush-sized (~15 cm), nondescript brown-grey. I noticed it had unusual behavior: It perches on a branch, then flies out about a meter, does a...

So I was building a Gaussian gun for physics filming it at 300fps. See video: http://youtu.be/hZcAk3uBp58 While skipping frame by frame, I realized that all the magnets started drifting backwards after being hit. Can someone explain in detail what is going on? Sorry if my physics is not...

Hi All, I think I have confused myself ... perhaps you can tell me where my reasoning is wrong. The idea is that in general coordinates the partial derivative of a vector, \frac{\partial A^i}{\partial x^j}, is not a tensor because an additional term arises (which is the motivation for...

I have to write 150 to 250 words on the behavior of air when the angle of attack of a wing increases. I have 2 graphs, one is on the Cl and the other on the Cd This is for the drag coefficient: http://www.plaatjesdump.nl/upload/89b3970a883a30f9fb840a6982d2859c.jpg This is the graph of the lift...

Homework Statement \lim_{x->0} x\sin\frac{1}{x} The Attempt at a Solution I can rewrite the function as \dfrac{\sin\frac{1}{x}}{1/x} But this can't be equal to 1 as the argument tends to infinity.

Hi, I recently designed a PCB in EAGLE, and I got it manufactured and I had all the pieces Sufrace Mounted on it, put it in the oven, everything seems fine and dandy, but I already killed 3 LEDs because of some weird thing going on. I have 5 different LEDs conneced to my circuit, the leds run...

Hello, I'm currently working on simulations in Solidworks of the flow of air (v = 450 m/s) around a sphere (radius = 1.5 cm). The results have been used in a cut plot representing the velocity in the x direction. The image is similar to this one...

Can somobody help me how to get the 2.72 and 2.73 equation?? http://imageshack.com/a/img89/5594/kiw6.jpg

Ok so i have the equation y'=y^2(y-3)(y-5)^3 I found the equilibrium positions to be y=0, y=3, y=5. For my phase diagram all the arrows are pointing up so the solutions are nodes? The last part asks Describe the long term behavior of the solution to the above differential equation with...

There was a thread a while ago regarding a capacitor where the capacitance was changed while it was part of a circuit. I won't link the thread here as it was kind of a train wreck... Now the explanation given was that in order to change the capacitance work would have to be done to cause...

First, I'm not asking for medical advice; don't get the wrong idea and delete the thread. I've been all around the world, slept in hostels, dorms, things like that. I've seen people do some strange stuff. People who seem to only sleep a few hours at night, but talk in their sleep, actually sit...

Hello I am building a set of data. It is composed of events that occur at discrete times throughout a day. There is tolerance, eg. per 5 seconds. I want to be able to predict the probability that an event will occur at a given time on a future day, by taking the probability derived from...

So I was sitting in my very low level biology class today, and we covered some basic chemical concepts that we will need for the class, basics of atoms, the periodic table, sub atomic particles ect... Then we got to the section on bonds, covalent bonds specifically. She showed the typical...

Hello everyone, I have a really interesting question here. I am measuring the factor of friction between two different metals. My results are a beat cloudy. When I use Steel - Brass surfaces the factor of friction, μ is being reduced while I am increasing the applied force. In other side, when I...

http://www.pnas.org/content/early/2012/02/21/1118373109.full.pdf

I have an interesting question. I believe this would be the appropriate spot to post this as well. I understand that light is both a wave and a particle, or can be perceived as one or the other in specific circumstances, known as wave-particle duality. So my question is this, under such...

Homework Statement Some gas is heated in a sealed container. How do the average distance between the gas molecules, and the frequency of the molecules' collision with the walls, change when the container (A) has a fixed volume, and (B) is allowed to expand outwards? The attempt...

Homework Statement The differential equation is y' = y^2 Draw a direction field for the given differential equation. Based on the direction field, determine the behavior of y as t →∞. If this behavior depends on the initial value of y at t =0, describe this dependency.Homework Equations The...

I really would appreciate seeing what opinions* there are on undefined behavior in C. Based on only the code snippets (A, B, C, D, E (yes, they have issues)) below and: From N1570 (C 11 standard draft) http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf This is what the standard says...

After a female mosquito that is inside a house feeds on the blood of a human occupant is there any mosquito behavior that helps it successfully get outside to lay its eggs? (Or are there suitable places inside most homes where mosquito eggs can be laid? In the the USA, the only common...

What happens to electrons at 0 Kelvin? I know in theory all atomic motion stops (vibrational energy = 0), and that the electrons occupy the lowest energy levels. But it seems the electrons would have to still be orbiting or occupying non-localized states, and thus have kinetic energy? Can...

So there's a new paper out by Yves Couder's group that observes quantum mechanical-like wave dynamics by averaging the long-term dynamics in a purely classical system. In other words, it's hidden variables. http://web.mit.edu/newsoffice/2013/when-fluid-dynamics-mimic-quantum-mechanics-0729.html...

(I am not sure what is the best subforum for this doubt, please move the thread if necessary) When we study the interaction of the electromagnetic waves with a charged particle (let's say an electron) we can find two totally different approaches in the literature. If we are talking about light...

Let's say we pass a photon through a 0 degree polarizer. the photon is now oriented at 0 degrees, meaning it will pass through subsequent polarizeres oriented at 0 degrees. (note - Not all photons will pass through the 0 degree polarizer, roughly 50% will pass through. we are talking about...

Here is the question: Here is a link to the question: How to find the intervals of increase and decrease? - Yahoo! Answers I have posted a link there to this topic so the OP can find my response.

Why can't quantum behavior be explained as an extreme version of classical behavior? For instance, the idea of a small quantum particle being in superposition could be explained by that particle switching between 2 or more states at an extremely high frequency. How high a frequency? Well, on...

dy/dt = 2 - 2ty y(0) = 1 I am not asked to solve this (I know it's not easy to solve), but what I am asked is, "for large values of t is the solution y(t) greater than, less than, or equal to 1/t"? I would think less than because 1/e^(t^2) converges faster than 1/t, but at the same...

Any help is appreciated, thanks. Homework Statement In my course of differentials equations we were given the task to model a real life system with them, we choosed something that resembles a pendulum.Homework Equations The Attempt at a Solution We went to the lab and got experimental data from...

I am looking for a definition of sound. Does it have anything to do with what is perceived by the ear, and therefore restricted to certain frequencies? Is it even a perception or is it simply a longitudinal wave? I can find lots of physics material about sound, but I can't find a definition.