Explain Definition and 1000 Threads

explain this C programme?? #include<stdio.h> void func (int x); void func(int x) { if (x>0) func(x-1); printf("%d",x); } int main() { func(4); return 0; } this C programme gives the output of 0 1 2 3 4 can anyone explain me how this happens I am totally confused ...

hi, i want a book that introduce the heading of quantum maths and explain their from basic to advanced. if this book there is in internet free, please send it's link.

After the link to TED was posted a few threads below, I began to browse through the videos and I found this one which I liked a lot. http://www.youtube.com/watch?v=5hJCxSiH4ts&feature=channel_page I got questions 1 and 2 right. But the 3rd and 4th questions wrong and along the lines of the...

Did Einstein ever say how he came up with the fact that the speed of light is always constant .

Hi everyone ! I´m posting as I couldn´t find any information on the forum, or maybe I can´t find a way of searching. My question is based on a discussion me and my girlfriend had about "making yourself heavier", and we tried a little experiment: First I lifted her in my arms without any...

Hi I'm trying to get my head around this plot of the cosmic microwave background radiation. http://www.astro.ucla.edu/~wright/CMB-LCDM-w-WMAP.gif I've been searching all around to find out what exactly a angular power spectrum is. I know what an ordinary power spectrum is. I'm a second...

I was wondering, why is it that the planets orbit in elipses? I find it strange that it's path would be eliptical, is it the result of some kind of force of nature keeping it fixed in it's orbit? Or is that simply the way it is? I can't help but feel there's something deeper to it...

Hello everyone, Right now I'm working on an inclined plane problem. "a) The worker exerts a force(F) of 86 N. How much work does he do? (b) How much work is done by gravity? (Be careful with the signs you use.) (c) The coefficient of friction is µ = 0.20. How much work is done by...

according to leibniz, if i have a series (An) with an alternating sign, in order for the series to converge, i need either |An| to converge, or |An| to diverge and An=0(for n->infinity) and A(n)>A(n+1) BUT in the following series where An= ((-1)^(n-1))*1/(n+100sin(n)) the series |An|...

Electrical permittivity...in mathematical terms, i.e I need the derivation...WITHOUT using 'curls'. Didn't find it online.

Hey guys. I've started studying Physics at home, but only the theory side with a little mathematics. So i would like to try, if i can, to introduce a little calculus to my work. But the problem is i find calculus a mind boggle, i understand All the GCSE math that i did. Could someone explain to...

so apparently 3^-1 mod 5 = 2 so (1/3) mod 5 = 2 I don't get how this works, can someone explain?

Homework Statement A 55kg mass is tied to a massless rope wrapped around a solid cylindrical drum. The drum is mounted on a frictionless horizontal axle. When the mass is released, it falls with acceleration 1.0m/s^2 . Find the tension in the rope. my answer : 484N the way I got is...

As I understand it, when Schroedinger's "box" is opened, then a dead cat comes into existence in one universe and a live cat in another. However, in a variation to this experiment, in which there is say a 10% chance of the cat living and 90% dying, when the box is opened does one live cat come...

My teacher had a long metal pole (I believe it was aluminum) and said that it was NOT magnetized. He put a magnet up to the side of the pole and it did not stick, and he dropped a marker through the top of the pole and the marker came out the bottom at a normal rate. However, when he took a...

Although Albert Einstein had explained the new picture of gravity through his theory of general relativity, by explaining that gravity is the warping of spacetime, did he explain why mass actually warps this fabric of spacetime?

Can anyone explain this "self healing" mystery. Can anyone think of any type of failure mode in an electronic component that could account for the following weird case of my self healing LCD monitor. ---------------------------------------- I've got this LCD monitor that's got a weird...

It appears that the Dark Energy concept was born out of a need to explain the two major observational phenomenons (increasing rate of expansion of the Universe and the faster-than-expectated-rotation of the galactic outer-rim). If I'm not mistaken, this also has to do with gravity seemingly...

If you can answer any of the questions below, your help will be greatly appreciated. There's an equation from E&M (I believe the definition of the antisymmetric field tensor) that reads: F_{\mu \nu} = \frac{\partial A_\nu}{\partial x^\mu} - \frac{\partial A_\mu}{\partial x^\nu}...

I'm not going to blame anyone except for the fact that I'm probably a slow learner. Can somebody explain some of the things I'm learning in layman terms? That way I can have some context when I'm reading about them. Right now, the things I'm reading have no meaning, so it's really hard to...

I have become very interested in physics and astronomy recently and have started dabbling. I have been reading about curved space time and its association with gravity. I've also been reading about time as it is related to travel at the speed of light. Can anyone explain the concept of...

My professor just told me that if \Delta x is small, then we can expand L(x+\Delta x) as follows: L(x + \Delta x) = L(x) + \frac{d L}{d x} \Delta x + \frac{1}{2!} \frac{d^2 L}{d x^2} (\Delta x)^2 + \ldots, where each of the derivatives above is evaluated at x. Could someone please...

The integral is \int_0^{f(E)} \frac{\cosh \alpha x}{\sqrt{1-\beta \cosh^2 \alpha x}} dx, where f(E) = \frac{1}{\alpha}\cosh^{-1}(\sqrt{\frac{1}{\beta}}), \alpha > 0, and 0<\beta<1. The integral has proven very difficult to evaluate. Every time I plug it into Mathematica with values for...

Hey guys, I was just wondering what the difference between these two statements are: V¯(x) = ± 4 V¯(x) = - 4 ---> does not exist. This is the quote from my text, "...we remind you of a very important agreement in mathematics. The square root sign V¯ always means take the positive...

Can someone please explain this remark in Landau-Lifshitz's *Mechanics* about fields? On pg. 15, it says that "individual components [of momentum] may be conserved even in the presence of an external field." What do they mean, exactly, by "external field?" I know (or at least I think I...

(i) if \alpha=\sum_i \alpha_i(x) dx_i \in \Omega^1, \beta=\sum_j \beta_j(x) dx_j then\alpha \wedge \beta = \sum_{i,j} \alpha_i(x) \beta_j(x) dx_i \wdge dx_j \in \Omega^2 NOW THE STEP I DON'T FOLLOW - he jumps to this in the lecture notes: \alpha \wedge \beta = \sum_{i<j} (\alpha_i...

http://img209.imageshack.us/img209/4922/14662031eo8.jpg

http://img209.imageshack.us/img209/4922/14662031eo8.jpg

Can some kind person please explain why He-4 is so high and Li-6 is so low on the graph of binding energy per nucleon. Copy of the graph here http://en.wikipedia.org/wiki/File:Binding_energy_curve_-_common_isotopes.svg" It means that He-4 must be very stable right? Because binding energy is...

Can someone explain Charpit's Method to me (PDEs) ! Thanks

Homework Statement Initially the switch is closed in the circuit shown and the light bulb is shining brightly. What happens when the switch is opened? (diagram in attached link) 1. The bulb goes out immediately. 2. The bulb gets gradually brighter. 3. The bulb gets gradually dimmer...

I'm trying to study a proof for a quiz right now, and even though I have the answer, I don't get it because I don't understand what an orbit is. I got no definition in class, and can't find anything in the book. I looked on wikipedia, but that was completely over my head. Can someone please...

I am learning linear response theory right now and I have come across a mathematical technique I have seen before but I don't understand the reason for the application. What I am talking about is the insertion of the sum of basis vectors in the commutator. Generally speaking it looks similar to...

Why we are searching quantum gravity effect at the Planck scale? The question seems very stupid (and may be) but let me explain. I define a quantum object when his action is of the order of Planck constant \bar h. namely A~E \delta t~\bar h. So if i take a small amount of energy E i can take...

Homework Statement The reference frame K' moves in the positive direction of the x-axis of the frame K with a relative velocity V. Suppose that at the moment when the origins of coordinates O and O' coincide, the clock readings at these points are equal to zero in both frames. Find the...

Mechanics & physics,can anyone please explain the scenarios?Very practical Questions? Hi...Can anyone please be kind enough to help me? i know it will take a bit longer for u to answer. I have some scenarios and questions in the following pages...

I am reading a paper that uses a quantum mechanical notation that I do not understand. I have found a webpage that explains it, but I do not understand the explanation either: http://chsfpc5.chem.ncsu.edu/~franzen/CH ... (let Y represent the Psi) Specifically, I understand what <Yn|A|Yn>...

The problem comes down to this: At a gameshow there are three doors. Behind two of them there is a goat, and behind one is a car. You pick a door. The gameshow host, who knows where the car is, then opens one door that you didn't pick, but contains a goat. You are then allowed to change your...

Can anyone explain the physical meaning of "spin" in QM? I'm a physics master student and I've completed several quantum mechanics (or related) courses and i have no problem working with Pauli spin matrices, angular momentum L, spin momentum S and total momentum J for nuclear or atomic...

Can you explain to me... How Will Smith was "voted" (?) the top moneymaking movie star in 2008 by theater owners? http://www.usatoday.com/life/movies/news/2009-01-02-smith-top-moneymaker_N.htm He had two movies out, Hancock and Seven Pounds, which together grossed $267 million. But The Dark...

I wonder if quantum gravity effects can explain Inflation after the Big Bang? For example, in Loop Quantum Gravity, there are area and volume operators and eigenvalues, etc. Would there be jumps from one volume state to another with time? Thanks.

Hi, I was wondering what really ARE spectral lines? Are they electromagnetic waves? But still they are affected by magnetic & electric field in the Zeeman and Starks effect respectively, whereas the electromagnetic waves are not. so is there any theory explaining...

In an attempt to grow stronger (i'm quite feeble to be honest) I've decided to start doing dumbbell excercises. However, I'm quite curious - what actually causes muscle development? As in the process, what occurs in the body for it to occur, etc. Thanks in advance.

I've been trying to put this together in my head for a while and it doesn't come out. For example, if there are more stars on one half of the sky, does it mean that a thrown object will travel faster in that direction? If the object is at the edge of the universe, does it mean it will not be...

can anyone explain me about the bigbang singularity

was changed to a new thread... https://www.physicsforums.com/showthread.php?t=277401 thanks

I still need someone smart to explain 2 me momentum and Impulse throughly... 1. A hunter has rifle that can fire a.05 kg bullets with a speed of 900 m/s. A 40 kg leapord springs at him at 10 mm/s. How many bullets would the hunter need to stop the tiger dead in its tracks...

Explain differential equation of order 3? With example?

Can someone please explain how to compute this integral? This is not for school; I just came across it and I'm not sure what to do. Parts and various identities didn't help. \int x/tan(x) dx

Homework Statement A sphere completely submerged in water is tethered to the bottom with a string. The tension in the string is one-third the weight of the sphere. What is the density of the sphere Homework Equations Here is the solution to this problem. It is problem 15.17, the...