Explain Definition and 1000 Threads

My idea of explaining time dilation to others (average people) was : see a light wave as the time, person A standing still sees the time (light wave) passing, person B moving sees lesser time passing when going in the direction of the light wave (while "looking" to the light wave) because he is...

So, Shankar in his famous book started to use the propagator a bunch of times in his Simple Problems in One Dimension chapter, and I have been confused to what it is and does.

I'm asking this integral equation (I'm not sure if it's an integral equation or not by it's a problem in my ODE book and because it has an integral in it I called it that way). anyways, this is the problem: y=\int^{x}_{1}ty(t)dt I differentiated y with respect to x and I turned that equation...

why carbon can form polymers and sillicon not? though both are tetra valent. explain this based on its orbital and bonding energies

Finding out about the past (archaeology) always involves digging down? Does this mean that the planet we live on is actually expanding? If you think about the programs on the TV! E.G. Time team, they are always digging down to find our (the planets) past. Now considering the above, Can we...

The other day, as I was struggling through my quantum mechanics text, I realized that the only physical laws presented in the text were the four postulates of QM, the last of which is Schrodinger's equation. These are presented around page 150. The first 150 pages establish the background needed...

So I have some unresolved issues with relativity in general (as in both SR and GR) which I would like to bring up and then discuss: First, Cosmic Limit: It is logical to find that c = maximum velocity, but what is the maximum possible acceleration? No form of non asymptotic acceleration...

This might look a bit stupid but I have just started beams and I can't understand a part in this example it is to do with finding a general equation of the height at any given point on a tapered cantilever beam can someone please explain

Homework Statement I was helping my sister with her high school geometry homework, and she had to graph the absolute value function y=lx+6l using two linear equations. The way i did it was different than the way her book showed. Basically, I told her that when removing the absolute value you...

Homework Statement...

A double slit experiment which has two stages: first the experimenter marks through which slit each photon went, without disturbing their movement, and demonstrates that the interference pattern is destroyed. This stage shows that it is the existence of the "which-path" information which causes...

Dear Marcus: Many thanks for your very informative messages. Please write one more on a simple LAYMAN's question. How do we know FOR SURE what is going on NOW in the far distant places of the Universe as the light from there had originated long AGO? Why there are no chances that NOW...

http://books.google.com/books?id=Ey94E3sOMA0C&lpg=PP1&pg=PA190#v=onepage&q&f=false" Aristotle's Logic I want to know whether I have understood this right. We shouldn't be saying , "All Greeks are men,all greeks are white,therefore some men are white". So we should be saying "there are...

Indicate why we can impose only n initial conditions on a solution of nth order linear differential equation. A) Given the equation y'' + py'+ qy = 0 explain why the value of y''(a) is determined by the values of y(a) and y'(a). B) Prove that the equation y'' - 2y' -5y =0 has the...

Homework Statement can anyone explain me about Integrals and derivatives in brief Homework Equations The Attempt at a Solution

Homework Statement Homework Equations V=IR, Nodal Analysis The Attempt at a Solution 1 and 2 in the diagram are the nodal equations. Considering that the left node is V1 and that the right node is V2. I don't know how to get from the nodal equations to step 3. I know that you go...

Homework Statement Homework Equations V=IR, Nodal Analysis The Attempt at a Solution 1 and 2 in the diagram are the nodal equations. Considering that the left node is V1 and that the right node is V2. I don't know how to get from the nodal equations to step 3. I know that you go from step...

Let's say I have an equation E=iE0cos(kz-wt)-jE0cos(kz-wt), how do I look at this and know, this is linearly polarized? or what if it changes and the kz is negative? or its a sin function with with (wt-kz-pi/4) in it. I just don't understand what this equation is supposed to be telling me and...

I just pulled a paragraph that's giving me a headache atm. http://img31.imageshack.us/img31/8697/unledwjt.png The LOP (Figure 2.1) they refer to is [PLAIN][PLAIN]http://img600.imageshack.us/img600/9787/unledylv.png How on Earth did they show that this feasible set is bounded? Yes I...

CAN SOMEONE PLEASE explain the "this." keyword in java to me?! "the this keyword can be used to refer to the calling object or used inside one constructor to invoke another in its own class. I understand how it invokes another constructor. But i do not understand why i keep seeing this code...

Hello all, New member here, I am in need of someone familiar with Physics to explain something to me. Its 9-11 conspiracy related so apologies to anyone who is sick of that subject but a someone has posted a stack of formula in response to a comment of mine and I would like someone who...

can i use cvt to act like the resistance load in the generator? to analyse if the output power is increase or decrease... its about my degree project...

The question was, Explain instantaneous velocity. My answer: Limit as delta(t) approaches zero of average velocity is inst. velocity. Or as delta(t) approaches zero, average velocity approaches inst. velocity. inst. velocity is the slope of the tangent line at a given point... Then I...

i am confused about the railguns electro-magnetic action please somebody explain if possible.

Homework Statement Consider two points located at r1 and r2, separated by distance r=(r1-r2). Find a vector A from the origin to a point on the line between r1 and r2 at distance xr from the point at r1, where x is some number Homework Equations The Attempt at a Solution I have no...

Homework Statement I have a question that states "Explain quantitatively why BLAH is true". What does "Explain quantitatively" mean? Homework Equations None The Attempt at a Solution I think it means give an outline of the argument, however the word quantity makes me think it...

Homework Statement For drawing purposes, I'm just going to state the locations of the 2 points. Cable AB carries a tension of 12 kN. Point A=(0,0,70) m and point B=(35,-25,10) m. Find the corresponding force on point B as a vector. okay now this part has me confused. I'm trying to...

From the wikipedia page on his "The Structure of Scientific Revolutions" Can somebody explain what is meant? The way I see it, it seems so obviously wrong: I don't see any reason why two opposing paradigms can't be tested by the same experiment... For example you had the Phlogiston theory...

\frac{1}{|\partial B(x,r)|}\int_{\partial B(x,r)}u(y)\,dS(y)=\frac{1}{|\partial B(0,1)|}\int_{\partial B(0,1)} u(x+rz)\,dS(z) Why does dS(y)\to dS(z) and not dS(y)\to dS(x+rz)? If you want more information, it comes from http://www.stanford.edu/class/math220b/handouts/laplace.pdf on page 8...

Given that the Lorentz force on a current when E=0 exists only at right angles to the current, such would not change the speed of the current, but only its direction. Also, when the current is parallel to a magnetic field line, no deflection of the current by the magnetic field occurs. A magnet...

A sample of liquid is heated from room temperature to just below the boiling point. The overall change in temperature is 75°C. Express this temperature change in kelvins. The book has the answer as 75K. How did they arrive at that answer? I don't think I understand the problem. I rather...

Homework Statement Ok so my book says that the volume of a parallelepiped is: V= |b cross c||a||cos(theta)| = |a dot (b cross c)|, where a, b, and c are vectors I get the "|b cross c||a||cos(theta)|" part because I can see the geometry but I don't get how they get from that to |a dot...

Hi, Can anyone explain why in field theory we require [f*(x),f(y)] = 0 for space-lkie intervals x,y; but not <0|f*(x)f(y)|0> = 0? Thanks!

I'm taking AP Bio and we're covering basic chemistry needed for it. I've not had chemistry yet, so I'm left wondering about the interesting stuff, like electronegativity. Basically, what I'm interested in, is: why is H2O polar? What is it about O that makes it magnetically attract H...

I was looking in my old physics text in connection with another thread and the text said high speed electron collisions and slow speed drift of electrons with an applied electric field don't explain resistivity very well...yielding resistivities 100 times or more than observed. For a plain...

Hi All, I wonder if the modulation of RF waves (Amplitude Modulation, Frequency Modulation, and Phase Modulation) can be explained in terms of photons. Thanks, Srini

Now, from what I understand, Bohr's model of the atom is outdated and flawed. But whenever I imagine energy levels, it is the Bohr's model that comes to mind. Do electrons really orbit around the nucleus? I would assume because of classical physics, even though the electron can be on any portion...

Too few examples to explain "The principles of quantum mechanics" by dirac. Hi! I studied my first course of quantum physics without a technical formalism (I'm studying physics engineering). I find some hindrances in paragraph 20. It says (I'm translating from Italian): After a few...

Regarding the problem of the low entropy state at the big bang, people like Penrose, Page, Carroll etc. do not think that inflation solves the problem. I recently read and listen to Seth Lloyd and his explanations about the beginning of the universe from the point of view of entropy as...

Hi Guys, I have a question. Can we attempt to explain the phase change of a carrier wave in terms of photons? For example consider GPS signal. It is BPSK modulated, in which phase change of 180 degrees happens for multiple of 1540 cycles of the carrier. How is the phase information...

Was Super String theory (theory that attempts to unite General Relativity and the Standard Model of particle physics) specifically designed to explain singularities; ie: phenomena such as black holes and the big bang? Does all other phenomena obey, and can be explained, by either classical...

[b]1. Homework Statement [/ Using the approximation, explain why the second derivative test works approximation=f(x0+delta x, y0+delta y) delta x and delta y are small... Homework Equations f(x0+delta x,y0+delta y) The Attempt at a Solution ok so i know the first derivative...

What do people in the industry usually mean by steel cord? Is it the same as steel wire, steel rope? Pictures, Wiki, professional article/dictionary would be appreciated. I googled it but the results are still quite too blurry. Thanks in advance!

i do not understand why they graph it with a line and a circle. I know what the circle and the line mean, i just do not understand how they apply to this graph.

my teacher asked Explain why it is necessary to standardize your EDTA solution. I am not totally sure why it is important.. can some one explain?

Homework Statement explain, briefly, what a hysteresis cycle is [2 marks] The Attempt at a Solution I don't think the answer is to draw a graph because that is the next question. The subject is electricity and magnetism but the above question does not refer specifically to electricity...

I really like it, but haven't seen any good, simple descriptions of it! Is there any place to get just the overall gist of it?

I believe that it is correct, and it concisely represents a concept I have never understood. It seems obvious to me that the chance of getting the higher bill would be 50/50, and if you ran enough simulations then you would do no better by consistently choice to switch than by choosing to keep...

I. Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it. They say the Earth keeps spinning because it started spinning and now there is no external force applied to it to stop it. The Sun is an external force. I...

Homework Statement Half-Passage: In the packing industry, processing packages via conveyor belts is immensely practical and vital for operations. Maintaining packages in a neat and file line is no easy task, considering that many conveyor belts are non-linear and require the traversal of hills...