Concept Definition and 1000 Threads

Homework Statement Why are magnetic forces not always conservative? I came across this question and to my knowledge they are always conservative...can anyone explain why they wouldn't be?

Ok so I understand how a voltage source works, with electrons flowing from a high potential to a low potential. But I'm a little confused about solar cells. So the way they work is that an incoming photon strikes an electron and gives it enough energy to break free and create a current. But...

I've tried to understand this concept, but even the so-called "simplest" resources are too complicated to understand. Can anyone please explain this to me? Thanks in advance!

Homework Statement Strictly speaking, the description of Coulomb's law given on the previous page (written below this paragraph) is meant to apply to point charges. However, just as Newton was able to develop the mathematics(calculus) that proved the mass of any spherical object can be...

Hi, I'm having trouble thinking some physics concept in Wrestling/Judo/Shuai Jiao/Greco Roman Besides Gravity and friction... Help =/

Hey guys I have a question about how zener diodes usually work as voltage regulators in circuits. To my understanding, one can place a zener diode in any circuit to stabilize the voltage to the zener diode voltages rating for the whole circuit. This makes sense for one zener diode. I...

Homework Statement This is a concept question on a study guide I came across and I really didn't know how to answer it or think about it...I havn't seen anything like this question before How could you prepare a spherical chamber that has a uniform electric field everywhere inside?

Homework Statement Iron is a metal that exhibits magnetic properties, but most pieces of iron are not magnetic. Why? Homework Equations none The Attempt at a Solution I have no idea. I am very confused.

Homework Statement I've been reading my Linear Algebra Book for an hour now and from what I've read. Eigenvectors are vectors that satisfies Ax = λx, but I've noticed that Eigenvectors isn't the important thing here, it is the Eigenvalues that really have the "big" meaning. Ax = λx...

Homework Statement Suppose A\boldsymbol{x} = \lambda\boldsymbol{x} and A\boldsymbol{x} - \lambda\boldsymbol{x} = \boldsymbol{0} Then the \boldsymbol{x} (vectors) that form the eigenspace are the linearly independent set of eigenvectors assuming A\boldsymbol{x} - \lambda\boldsymbol{x} =...

So I googled and found out that brightness of a lightbulb is directly related to current, but for some reason it doesn't match the concept I have in my head. I know that a lightbulb gets brighter as it gets hotter (like any kind of metal) So for a lightbulb to get brighter, it needs more...

Homework Statement For what values of K is the following integral improper? \int\stackrel{K}{0}x^2 / (x^2-19x+90) dxI'm stuck on this question. I understand mechanically, that the integration require partial fraction decomp, which results in -9ln(x-9) (from 0 to K) + 10ln(x-10) (from 0 to...

Homework Statement A. Friction B. Impulse C. Momentum D. 3rd Law of Motion E. 2nd Law of Motion F. 1st Law of Motion G. Circular Motion H. Freely Falling I. ProjectileHomework Equations Write the letter of the concept/theory under the following physical situation. 1. Truck and car moving with...

Homework Statement A spherical cavity of radius 4.50 cm is at the center of a metal sphere of radius 18.0 cm. A point charge Q = 6.40 µC rests at the very center of the cavity, whereas the metal conductor carries no net charge. Determine the electric field at the following points. (a) 2.0...

Homework Statement Newton's 1st Law of Motion A ball rolled across the top of a pool table and slowly rolls to a stop. How would Aristotle interpret this behavior? Galileo? You? Newton's 2nd Law of Motion If a heavy person and a light person parachute together form the same altitude, and...

Homework Statement Just started learning vector spaces... not as fun as matrices. Anyway, I have a problem here, and I just want to make sure I'm understanding it correctly. It states: "The set {(x,y): x>/0; y>/0} with the standard operations in R^2." It asks me to prove whether or not it's a...

Greetings, I had an argument with my substitute Physics teacher about the use of the transistor and how important it is/was. Basically, we were debating whether or not it is important because of the invention or whether it was purely the concept that made it so important. His argument was...

Whats the Concept behind "change of electric/magnetic flux"? What i mean to say is that, i understand the concept of "change of distance", "change of time" and other changes and other time rates... but the "time rate of change of electric flux" really confuses me. Does change of flux mean...

Can someone verify these for me and explain? True/False No square matrix with real entries can obey A^2 = -I The only 2X2 matrix that obeys A^2 = 0 is A=0 The only 2X2 matrices that obey A^2=A are A=0 and A=I Much appreciated.

Hey all, I was reviewing the concepts of how to derive the formula for the surface area, namely.. SA=\int \int \left\|\frac{\partial \widetilde{r}}{\partial u} \times \frac{\partial \widetilde{r}}{\partial v}\right\| dA (I didn't know how to make vector arrows so I used the tilde sign.)...

Mechanics Kinematic General Concept question, not a numerical!? I'm really confused concerning the positive direction and the acceleration taken while concerning the motion of the ball! Well, the main thing that i wanted to ask is that if 2 balls are been projected at the same time in two...

Hey all. I'm not sure how conceptional questions work on this site... so I guess I'll try to attempt to answer them and you guys correct me if I'm wrong? Here goes: For the statement below, write true or rewrite the quoted portion to make the statement true. The "magnitude" of the magnetic...

Homework Statement Just to make certain that I am understanding this correctly, given a function f(z) = u(x,y) + iv(x,y), the existence of the satisfaction of the Cauchy-Riemann equations alone does not guarantee differentiability, but if those partial derivatives are continuous and the...

So this is the question... In the direct circuit diagram below (please see the attached file), Resistors 1 and 3 have fixed resistances (R1 and R3, respectively), which are known. Resistor 2 is a variable (or adjustable) resistor, and the resistance of Resistor 4 is unknown. Show that if...

I'm having a problem understand entropy. From my book, it says the following: There is an example that says that What I don't understand is if there is an increase in entropy, which is the increase in disorder, why does the hot water cool spontaneously when cooling the water makes the...

Can the concept of hybridization be applied to what we consider ionic, such as MgCl2 (sp hybridization, if we apply it)?

I'm currently a Junior in high school with an average GPA of about 3.197 (includes first semester of Junior year). Over the years, I haven't really been taking hs TOO seriously due to the lack of focus and effort in my studies (and also because I thought high school would be as easy as middle...

My engineering professor has always stressed that once you understand a concept you don't have to solve a lot of problems. He has also said that you don't need to memorize anything if you understand. My Question is, how do you understand a concept?

What is the true concept of resonance in particle physics? can particle production happen via resonance? how?

Why is the electric potential in the middle of two oppositely charged points 0? Does this also mean that there's no potential energy at this point?

Hey! I have some dumb-smart question Does 1D line have physical width? My logic says that mathematically you can go smaller and smaller,but I see there being a problem with 1D having infinitly small width in physics. If 2D object has infinitly many 1D lines that would suggest that 2D...

I'm currently trying to understand the concepts behind electric fields, flux, and Gauss's Law, so I'd appreciate it if someone could clear some things up for me. Flux is the amount of field lines that pass through a surface, so if there's a uniform electric field, will the net flux through...

Hi, I have been having trouble understanding this: Potential difference(Voltage) increases when charged particles travel against electric field lines. My question is why does the charge of the particle not affect Voltage? Why does an electron and a proton traveling in the same direction...

Hello. This is my first post! Thanks in advance for any help given. Homework Statement A constant electric field is in the positive X direction as shown in the diagram below. Also shown are two paths through which a charge can move from point A to point C. In the first path path the...

So I don't get the concept of specific heat. I'm doing an ODE problem and I've never even looked at science, not even in high school. The book defines the specific heat of a substance as: The ratio of the quantity of heat required to raise the temperature of a unit of substance by one degree...

Hi, I had an issue with compton scattering that I never received a satisfactory answer for. My issue was that after the collision, there exists a y component of momentum... but all diagrams of the compton effect align the axis center to center from the photon to the electron and on top of...

I have been given a question regarding op-amps. In the figure however, there are elements which have not been introduced nor explained in the chapter. Please refer to the attached image. (Image taken from "Microelectronic Circuits",by Sedra and Smith, 6th Ed., page 58.) In the figure there are...

This is first of questions, I may have more, hence the very general title of the thread. I know the basic optics involved, two most important things here are Snell's law and the concept of critical angle - no problems here, even if I am just skimming on the surface. Problems start when I am...

Homework Statement A ball (hollow sphere) of radius .11m and mass .444kg is mounted on a frictionless axle. A massless cord is wrapped around the ball supporting an object of mass .02kg. Find the angular acceleration of the wheel, linear acceleration of the object and tension in the cord...

Homework Statement I am reading about related rates in my calc book but it doesn't really explain it very well. Are there any arcitcals some one can send me that goes indepth about this concept on related rates? Thank you.

Homework Statement An object is moving in the +z direction. Which, if any, of the following statements do you know must be false? Check all that apply. 1. velocity of z is zero. 2. The net force on the object is in the -z direction. 3. The net force on the object is zero. 4. The net...

I have been searching the web for a good explanation of the concept of field but I failed to find a good one. Could somebody provide me with a good definition of this important concept of physics? I'm specially interested in its relation with waves. Thanks.

I don't understand why the lorentz factor is 1/[1-(v2/c2)]1/2 http://www.softcom.net/users/greebo/dila.jpg clearly you reach something different here.. i really don't get this, I'm sure it's something very simple

This is a different topic, not philosophy. In any empirical science, the scientists regularly scrutinize the concepts they are using---keep the definitions definite, the categories categorical, the distinctions sharp. It is an in-house function they normally do for themselves and do not farm out...

Hey, is infinity a concept or an actual number? This is a discussion with someone, I say it's a concept but then he brought up set theory, and I have no set theory knowledge whatsoever.

I always read in applications of integration is to figure out the arc length but they never tell us what is it good for I also couldn't find immediate results by using google, so can anyone tell me its uses?

Homework Statement 1. If an object is shot in a projectile path and its initial and final height is the same what is true. 2. If a rocket vertical is landing on the moon it shoots a bit of the rocket fuel while landing what is the correct Free body diagram. The Attempt at a...

So let's say a hydrogen is replaced with an oxygen. Apparently this is an oxidation. But I just don't see any transfer of electrons going on. All the atoms still have the same number of valence electrons. Can someone give me an example of a simple organic oxidation and explain the electron...

So I'm struggling trying to grasp the concept of momentum..due to my physics teacher going WAAAAAAAY too fast && i asked for help he didn't help much at all :\..so i asked my previous physics teacher i had before transferring classes because the school " said so " but it was a bit still...

This morning i spotted this paper. The concept of information is hot at the moment. but what is information ?.. http://arxiv.org/abs/1011.5039 Classical Information and Interpretation of Quantum Mechanics Authors: Marcin Ostrowski (Submitted on 23 Nov 2010) Abstract: This work is a...