Explanation Definition and 961 Threads

Homework Statement I was asked a very simple question today about finding the tension in a cable as a 1200kg elevator is accelerating downward at -1.05 m/s^2 . now I could answer the question easily ma = T - mg solve for T but what I couldn't answer was just the basic question when the...

Yesterday, my computer science teacher (intro course) mentioned this mythical P=NP problem. He tried to explain it to the class but it went over everyone's head. Could someone please explain it to me in laymen's terms? Thanks

I don't understand why an x boost followed by a y boost is different from a y boost followed by an x boost. Surely only the resultant velocity matters, and isn't time reversal a symmetry of SR? Similarly, why is the matrix for three simultaneous boosts any different from the product of boosts...

can anyone explain me about Pauli spin Matrices ?What is Pauli Spin Matrices ?

In this text is explained why our universe exists and why there are nature’s laws. The explanation is given in two parts: Part 1: Why does our universe exist? Part 2: Why does nature’s laws exist? The explanation uses concrete examples, to make the text as comprehensible as possible. At the...

can anyone explain a bit about Spin Quantum No ?.Kindly explain proerly.

Homework Statement My books doesn't seem to give a good explanation of tension vectors. I was hoping someone on here could explain them better. I put the picture from the book up. The two questions with pictures are the one's I'm having trouble with. In case you can't read them: The...

I've become interested in lasers and this question came to me today. Let's say we have two 10 mW lasers. One has a spot size of 1mm and one has a spot size of 10mm. Therefore, the first laser has a greater intensity. In classical physics we are told the wave amplitude increases. In modern...

Can anybody explain about Heisenberg's Uncertainty Particle.And Some Description in the experiment t o Prove the principle.

Can anybody explain me .About Rigid Rotator.Kindly let me know the idea.Any help would be highly appreciated.

Can anybody give Some Explanation about Momemet of inertia.Kindly let me know the idea Any help would be highly appreciated.

Shortly after the year 2001, to now, there have been more increasingly violent earthquakes, hurricanes, tsunamis, tornadoes, etc... than in any other decade in history. I wanted to know if there is a natural, geological, and meteorological explanation for this. Not too long ago, there were Two...

A non-technical explanation for "FTL" quasar motions I was trying to think of an accurate but non-technical explanation for quasar motions that seem to be faster than light, and I came up with one. A have a friend in Atlanta and he sends me a book via UPS. That book takes three days to get...

Consider a conical pendulum with a weight on it and that makes some angle with the vertical. I am told to find the radial acceleration of the weight and someone showed me how it is solved but I don't understand why: I am told to set Tsin@ = m(ar) *ar = radial acceleration ar = (Tsin@)/m...

can any1 explain what fermi level is simple explanation also how are minority charge carriers formed and i can't understand the energy band diagram of pn junction that how both the fermi levels become equal WHAT IS MEANT BY THAT FERMI LEVEL i read in hyperphysics but i can't understand it...

can some one explain me the qualitative aspects of RLC circuit i am satisfied with the vector diagrams i want the physical meaning behind say for instance in ac with inductor when current varies induced electric field is set up which opposes the current so there is a voltage drop similarly...

Hi all I read in a book that coherent means when two waves are monochromatic and have a definite phase relationship. What is meant by a definite phase relationship?

can some one explain me the qualitative aspects of RLC circuit i am satisfied with the vector diagrams i want the physical meaning behind say for instance in ac with inductor when current varies induced electric field is set up which opposes the current so there is a voltage drop similarly...

In the article from Wikipedia called: Geodesics as Hamiltonian Flows at: http://en.wikipedia.org/wiki/Geodesics_as_Hamiltonian_flows" It states the following: It is frequently said that geodesics are "straight lines in curved space". By using the Hamilton-Jacobi approach to the...

If you have dv/dt you say to yourself its the derivative of v with respect to t. But in an example of deriving the first kinematic equation for constant acceleration you go from a=dv/dt, to dv=a.dt and then you integrate this equation to give you the velocity. i.e v=u+1/2a(tsquared), using...

Greeetings, I am new to this forum and I have heard theat there is a simpler explanation of physics and I am interested what is it. Thanks in advance

Big derivative, just want to make sure I am doing correct thing here. a is the only changing dimension, r and l are constants ##\theta=\arccos\left(\frac{r^{2}+\left(r+l-a\right)^{2}-l^{2}}{2r\left(r+l-a\right)}\right)## I want to differentiate ##\frac{d\theta}{da}## So what I did was using...

You are stuck behind a slow driver, there is a 1 km passing lane between a slow car and a truck. In order to properly pass you must be at least 40m from the slow car. You are traveling at 70km/h and there is an oncoming truck traveling at 80km/h. Each car is 4m long. What is the minimum...

I am trying to understand the theory behind nuclear magnetic resonance. I have been reading various explanations (some more detailed than others) but I still have several holes in my understanding and I hope that some of you can help clear them up. I realize there are quite a lot of...

Experiments show that the following redox reaction is second-order overall: NO2(g) + CO(g) --> NO(g) + CO2(g) In the reaction, the initial [NO2] is twice the initial [CO]. What is the ratio of the initial rate to the rate at 50% completion? In the solution they say: [NO2]i = 2[CO]i...

Hello, so i was looking up the defintion of linear mapping and mapping in general and i have seen the technical defintion a few times but i was wondering if someone would mind explaining it to me in more general english. How would you explain it instead of just pointing out the definition...

I've read through a ton of material and still do not quite understand it. The way that we were taught was: 1) Redraw, with load removed 2) Redraw, find Voc 3) Redraw, find Rth 4) Redraw, using TEC with removed load Most of my questions involve finding Voc and Rth. I understand the steps...

You have a weight on one end of a piece of string and you run that piece of string through a tube, and then on the other end you attach a cork. You hold on to the tube and try and keep the cork spinning at a constant radius, such that the weight stays dangling at the same height. As you increase...

"...Recall that the n-side is studded throughout with positively charged donor ions, fixed firmly in their lattice sites. Normally, the excess positive charge of each of these ions is compensated electrically by one of the conduction band electrons. When an n-side electron diffuses across the...

I have already done this problem enough times forwards and backwards to get the answer, so this is more of a theory question rather than help with homework. The equation for Vavg.=displacement/time or deltaX/deltaT. This equate to V=(X2-X1)/(T2-T1), correct? In working through a problem...

I feel kinda stupid asking this, but can anyone give a simple explanation of the difference between Guass and strength of a magnet, and what exactly Guass is?

I've been getting confusing explanation on what negative voltage represents. In electrolytic cells my teacher explains that negative voltage means that voltage needs to be added for current to flow but in AC circuits I get the feel that negative voltage is applied in opposite direction than...

It seems to me that when 'randomness' is referred to, the explanation is always describing what 'random' behavior is not. I would equate 'random' with: no history, no dependence on intial conditions, no pattern, no predictable order. It only argues that 'random' behavior or outcomes are based on...

hi, i wanted a simple explanation of a series rlc circuit in a radio as i know the rlc circuit consists of resistor,inductor,capacitor i know the function of each of them but what i don't understand is how by combinig them we can make a radio tuner!? i searched many websites but i can't find a...

Solved! d/dx |x+2|^x Homework Statement I need someone to explain this: http://www.dafydd.se/stuff/solvethis.png Homework Equations I guess the following are of relevance... \frac{d}{dx} |x| = \frac{x}{|x|} \frac{d}{dx} a^x = a^x ln a The Attempt at a Solution The...

Seeking "Point Particle" Explanation Ahoy, For some time I've been reading through various topics in theses Forums as a Guest, but decided to move beyond that. I'm unfortunately not adept with Science or Mathematics (I'm more adept in Langauge and in Words), but I've always found them...

Homework Statement In Fig. 17-35, sound with a 46.4 cm wavelength travels rightward from a source and through a tube that consists of a straight portion and a half-circle. Part of the sound wave travels through the half-circle and then rejoins the rest of the wave, which goes directly through...

Hello, I came across the following explanation of E-mc^2 on pbs.org: "So why would you have to multiply the mass of that walnut by the speed of light to determine how much energy is bound up inside it? The reason is that whenever you convert part of a walnut or any other piece of matter...

I just read this article (http://physics.bu.edu/~duffy/PY106/Potential.html). I am stuck on just one line where it says that potential energy is in negative...please read this and explain... """""[FONT="Microsoft Sans Serif"]An example : Ionization energy of the electron in a hydrogen atom...

http://www.mysteryspot.com/ How do you explain what you experience there? I understand it's all optical illusion. I can explain - people walking on the wall, pendulum swinging at an angle - is just a slant-walled house. The thing I could not explain is the relative height difference...

Can anyone provide a brief explanation what an EM mode is? I've read some EM theory, but still have problems understanding what a mode really is! I know for some EM waves, the medium supports only certain modes, but is the 'mode' a property of a medium? Or is it something that should be...

I want to understand the higgs field more, but all the explanations i read i only slightly understand. Even that explanation of the celebrity walking into a room just made me more confused. Why does the higgs field gives objects mass? and how is the higgs field created? I want to know more but...

The demonstration: A mass of 2kg is hanged to a string that is hanged vertically from a fixture. Another string is attached to the bottom of the mass and then this bottom string is given a downward pull. Note that the strings used are assumed identical. This demonstration can be found here...

Homework Statement Given the following sum, turn it into an integral: \lim_{n \to \infty}\Sigma^n_{k=1}\dfrac{1}{n\sqrt{1+(k/n)^2}} Homework Equations The answer says =\int^2_1\dfrac{1}{\sqrt{1+x^2}} The Attempt at a Solution I understand how to get the equation, but why...

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Explanation of "net torque" in a problem I hate to ask such a simple question, but I was working on a problem where the idea of "net torque" was calculated differently than I thought. I more or less and just looking for the flaw in my logic and an explanation. :smile: Here's the main...

Why does running before jumping help you jump higher? The only explanation I could think of was that right before the jump you redirect your speed into the ground and compress your bones. This compression gets translated into an upward thrust when they expand again. What do you think? Thanks

Is it true that when a lower voltage is applied across an inductor it burns up the coil? If so can someone please explain why?

How can quantum mechanics propose an explanation of the mass and charge of the proton using particles with partial charges and guessed at mass but ignore the mass and charge of the electron?

Hi, I'm totally lost on how inflation solves the horizon and flatness problem. Flatness Problem Explanation I have d/dt(1/Ha)<0 and therefore |\Omega-1| is driven towards zero rather than away from it. My Confusion Doesn't inflation increase the volume of the universe...