Concept Definition and 1000 Threads

I am having trouble wrapping my head around the concept of the constant speed of light. Imagine I am moving in a ship at a certain speed (let's say 1/4 the speed of light). I send two probes out at the same speed, one directly ahead of me, one directly behind me. They are set to activate a...

Current Electricity: Help understanding concept of "potential energy" This is not a problem that I need help with. I rambled on and on for 5 minutes with teacher, eventually giving in and pretending that I understood.. http://i80.photobucket.com/albums/j199/pugfug90/CEPE.gif Umm.. Perhaps...

How does a small change in base current result in a large change in collector current in a BJT? Please explain in terms of movement of electrons (in NPN). Most textbooks I have referred say that the reason is low resistance of emitter-base and high resistance of collecter-base. However i cannot...

Hey guys, I’m currently working with a personal water craft docking company that is trying to redesign there current port series models into something that can capture the market as well as be designed to hold future personal water crafts i.e. jet skis and there future bulkier sizes and...

I am studying divergence and curl in my E&M class. I was wondering, why is divergence a useful concept? I mean, for point charges, the divergence is zero everywhere except where the charge is located. Even for charged surfaces, \nabla\cdot E = \frac{\rho}{\epsilon} Loooking at this it seems...

I have some confusion about what 'radiance' means as used in radiometry; specifically, I don't understand what it is a function of. For example: radiant energy is specified over some region, radiant energy density is specified at a point, radiant flux is specified across some surface...

I am having trouble understanding the concept of the effects on an orbit. The question asks if we replaced the sun with a rock of the same mass, would Earth's orbit change? I think it doesn't because orbits don't change because of its orbital energy. but I'm not sure because i wonder if the...

Hi, I'm looking for some information about effective potential, but I haven't found any (Wikipedia, Googled...). I was just willing to get a rough understanding of the concept, and understand what it is. Could you explain/link to good info please? Thank you very much.

I cannot understand how to apply the concept of relative velocity in certaijn questions like the below one the question is Two trains A and B of length 400m each are moving on two parallel tracks with a uniform speed of 72km/hr in the same direction with A ahead of B The driver of B decides to...

I've come across the Kondo effect in my research and specifically measuring the Kondo resonance. Now I'm sure I don't need to be an expert but I having some trouble clearing the concepts, the actual physics in my head. I know the Kondo effect is an exchange of spin do to an interaction...

Homework Statement http://xs511.xs.to/xs511/07046/workenergy.JPG Homework Equations The Attempt at a Solution Ok I am all confused on this one. ok so leave part (I) and (II) onto part (III) word done by the pulling force acting on the block = the loss of energy + work...

Homework Statement This is more like a concept question. If you have a solenoid with AC frequency f, placed in close proximity on top of a wire with both ends fixed, and projected parallel to it, why is the frequency of the standing wave observed in the wire equal to 2f? The Attempt...

hi everyone, I am just learning the taylor series at school. I am slightly confused. in my textbook, one of hte exercises is to find hte nth degree taylor polynomial of x^4 about a=-1. n is 4 in this case so this gives me a long polynomial. i understand that inputting any x value into this...

So a previous problem said to show that the area of some simple closed curve C was: A= \frac{1}{2} \oint_{C} (xdy - ydx) Simple enough. My problem says to find the area of the curve x^{2/3} + y^{2/3} = 4 using that formula. So off to polar coordinate land I go. r = 4, x = cos(t), dx =...

sir i haven`t good idea about function analysis &limit&continuity pls send me the message containing all this thankyou sir

"When a ball is dropped to the floor from a height h, it strikes the ground and briefly undergoes a change of shape before rebounding to a max ht. less than h. Explain why it does not return to the same height h." Is this because some of the kinetic energy is transferred to heat?? What does...

hmm I don't think I have the concept of the wronksian down all the way yet. mainly I'm having trouble seeing how the the wronksian not equaling zero implies that all the solutions are linearly independant of each other.

OK, I'm having trouble with this and can't seem to find an explanation for it. So To start off, i understand gravitational force, which is always just m*g (mass * -9.8 m/s). Now, when an object is moved by a force either horizontally or up an incline, etc. how do you figure out the work done...

[SOLVED] Why is push gravity concept considered not viable by mainstream science? Hello guys, I would like to know the main reasons why the push gravity concept is not considered as a viable concept by mainstream science. I know it gave rise to numerous published works, amongst which we have...

Here is the given problem: http://img213.imageshack.us/img213/6781/problemtk6.jpg Here is my incorrect solution: http://img152.imageshack.us/img152/6698/solutionzm3.jpg Why should distance even matter for the final velocity in this problem since once the spring is uncompressed...

I'm trying to understand the utility of the concept of apparent weight. I'm not trying to over throw centuries of science, but it just seems not to be very useful to me. Why is it useful to say 'the apparent weight in an accelerating elevator is more (less)' rather than to just say 'you weigh...

I guess this is going to be my worst thread. I'm so sick of this stupid concept "relative velocity" that I'm in no mood to present this thread in my "exemplary style" for which i have been included in the "best homework threads" section. I'm sorry for that, but its true. I have no problems...

A 0.6 kg baseball is dropped out of a window that is 6.1 m above the ground. The ball is caught by a person whose hands are 1.5m above the ground. Questions What is the gravitational potential energy of the baseball, relative to the ground --When it is caught? (Is this -27.05 J ?) --when...

Three objects with masses m1 = 4.0 kg, m2 = 10.0 kg, and m3 = 15.0 kg, respectively, are attached by strings over frictionless pulleys, as indicated in Figure P5.32. The horizontal surface is frictionless and the system is released from rest. Using energy concepts, find the speed of m3 after it...

Can someone please explain to me the concept of equilibrium because i am having trouble understanding it. Thanks

Hi all (it has been a while again), I have just started Universtiy and after my second lecture I was given a question sheet to complete in two weeks. I have completed 14 out of the 16 questions set, 2 of which I just haven't done yet and another will require a little more thought before I...

The problem is to rank the forces exerted from three blocks on top of each other. Like so: [10 kg] #3 [5 kg] #2 [2kg] #1 -------- Here is my reasoning, From least force, to most force: a. Force of block #1 on #3; They don't touch, so net force = 0 b. Force of #3 on #1; same thing...

Does anyone know of a good site that has good physics concept questions because our tests in class are 10 multiple choice questions--usually concept questions (since we can't use a calculator just like the AP Exam) and two free response questions. i need a little help with those concept...

Hey. I am having a little trouble understanding the concept of impulse. The textbook i am using doesn't really shed much light onto the topic. I know that impulse is equal to the change in momentum of an object, or the product of a force applied to an object and the time it is applied for...

Ok i am studing and the book doesn't give answers. Here are a few questions i gave. What do you think. I will list pictures and test. For pic/question 1 - Will the answer be d - roatating the loop 90 degree ? Would it make sense that since the magnetic field is going into the paper i...

look here: http://www.mut.ac.th/~physics/PhysicsMagic/wall.htm" scrolling to the motorcycle section, my question is, why is it that you cannot consider the point of contact of the motorcycle with the wall as a pivoting point? I have done some calculations, and this leads to a physically...

INTRODUCTION: I had been doing some current electricity froblems but now and then I'm having some problems with the distribution of current.I'm really confused. I have attached a figure with this thread, in which I've tried to combine all situations of current distribution in which I'm facing...

A child kicks a ball with an initial velocity of 8.5 meters per second at an angle of 35° with the horizontal, as shown. The ball has an initial vertical velocity of 4.9 meters per second and a total time of flight of 1.0 second. [Neglect air resistance.] what is the max height? what is the...

Ok, so I have a problem in which an object is thrown tangentialy to a surface which makes 45o with the orizontal. So we know, that there is an MOMENT OF FORCE, an instant acceleration, which give the object the initial velocity : Vo. The object is thrown in the upside direction(so is slowing...

A little concept problem with those vectors :) Ok, so I got two objects which somehow interacts to each other, or I have two electomagnetic waves which interact in that same way. I know the angle between those two vectors, and I know let's say the result vector of that impact, the module of...

I have a little problem with giving the solution for this question: Explain the concept of quantization on the example of energy levels for particle in the box of length L if the solution to Schroedinger equation is Psi = C sin ( sqrt( 2 m E ) / h x ) Maybe I don't understand this question...

Marlon: I'm having a bit of a crisis about particles. Can you tell me, what is your concept of a particle?

[SOLVED] Why is push gravity concept considered not viable by mainstream science? Hello guys, I would like to know the main reasons why the push gravity concept is not considered as a viable concept by mainstream science. I know it gave rise to numerous published works, amongst which we have...

I have a question in regards to displacement current. Is this theory mainly used to describe the field when a capacitor has a shape other than a flat one? Can anyone link me a site that clearly explains how we can use the concept of displacement current? From what I understand through...

What is mass ?? Text books define it as the "amount" of substance... You can also use some equations and toss Mass out, giving other definitions. But my question is about the wording "amount of substance" > What is this "amount of substance" ? > Because "amount" refers to counting.. How...

Hi, I just need a little bit of help with the concept of eigenvectors. I have a basic 2x2 matrix and have found the eigenvalues to be: 4 and 9 I have also tried going through the process of finding the eigenvectors that my lecturer has shown me, but I'm not sure where to go from there, I'm...

EPE...Verify this concept? I think I am on the verge of solving a question that has been bugging me for an hour or so but before I give myself a pat on the back can someone just have a look at a certain facet of the problem (that I will explain) and tell me if what I think is happening *is*...

http://www.gizmag.com/go/4936/ theres the link in case anyone hasnt seen it already. pretty simple concept, and it sounds like a great idea to me, but I don't quite understand 2 areas of the specific design, maybe somone can help. Firstly, is the heat from the exhaust gasses really enough...

First I had learned this definition of a "measurable function" (Apostol): "Let I be an interval. A function f: I -> R is said to be measurable on I if there exists a sequence of step functions (s_n(x) ) such that s_n(x) -> f(x) as n -> infinity for almost all x in I." But now in other...

Please someone of you help me in this concept. My Prof told us that if we need to move with contact with respect to an object, then friction is essential. I cannot think the dynamics behind it. There was a question was like somone jumped from a platform and we had to clculat the back velocity...

What does it really mean when forces are perpendicular to each other? Is it that they are independent of each other? And if so, why is that so special? I ask these questions to answer this homework question: Describe the path of a moving body whose acceleration is constant in magnitude at...

Hello everyone I have a slight problem. I am confused on how you know what path current is going to travel and also what voltage sources your suppose to add up to a specific resistor. For example here is my picture, already solved: The directions where to find the value of ix, the orignal...

I'm having trouble wrapping my head around this, can someone explain this to me? Thank you, Vincent

Do you think karma is a logically scientific concept and can be proven to be true?o:)

Does this have something to do with definite integration?