Concept Definition and 1000 Threads

could you explain if we can define a main/basic concept of math and if terminology corresponds to concepts or is chiefly due to historical reasons: set, set theory (ZF[C]) should be the founding concept, abstract algebra studies underlying sets, [elementary]arithmetics the result of logical...

why does adding equations solve the system of equations? I've taken matrix algebra but, to be honest, was too bashful to ask such a simple question. :P

I am trying to summarise the concept of divergence. Say I have a vector field, that is radially spreading outwards from the (0,0), but all vectors are equal in each point. So there are no deviations in magnitude in vectors(is that even possible?), but the field lines are spreading like in...

Hi there! I need some help in understanding the relationship between B and H fields and their "physical" meaning (helps me visualize problems). I'll try to be as clear as possible about my current knowledge and my questions: "Fields" do not exist, they are just a mathematical...

It looks like my first post on this did not make it on this forum some how. I came across this statement. Even though \frac{N_i}{N}=X_i, \frac{dN_i}{N}\neq dX_i How does this work? The book offered no help as well as searches on the internet.

hello world, We are studing about static fluids and i can't introduce the concept of pressure to my mind I can't imagine what is pressure?What is pressure at a point?I need images and iluustrations could you suggest for me some simple tutorials and some pages to read in order to fully imagine...

Homework Statement gammav is a reasonable measure of the size of relativistic effects. Roughly speaking, at what speed would observations deviate from classical expectations by 1%? Homework Equations gammav = 1/ [sqrt91.v2) / c2] The Attempt at a Solution I've honestly puzzled...

A gas expands according to the equation pv=1000. where p is pressure in kPa and v is specific volume m^3/kg. If the gas pressure drops from 1000 to 500kPa, how much work was done by the gas?? Ok I am new to thermo and given a question and can't figure it out. Do I use net flow work =...

The Draft of Poster of New Fusion Concept that I am going to represent at 53rd Annual Meeting organized by Plasma Physics Division of American Physical Society (attached file .zip) Without drawings yet but I will complete drawings till mentioned event.

I did search for this problem found a few but they were all different and I couldn't follow the math Homework Statement http://session.masteringphysics.com/problemAsset/1169191/1/jfk.Figure.20.P24.jpg What is the strength of the electric field at the position indicated by the dot in...

Hi all I am wondering about the concept of Mass in physics. What does it mean? , why we have different concepts of mass? , Why scientists anciently proposed two concepts of mass, inertial mass and gravitational mass? , Why they wondered if they are equivalent, while if i was a one of their...

With the advances in computers you can now get a server with phenomenal computing power and most homes have multiple computers in them. I'm interested in the concept of a single computer with 'access portals'. The access portals would be nothing more than a monitor and keyboard with the...

"The third point charge should be placed at a location at which the forces on the third charge due to each of the other two point charges cancel. There can be no such place except on the line between the two point charges." i need to be able to prove a similar statement mathematically...

My textbook says that Electrostatic potential is the work done on a unit charge to bring it from infinity to a point from a given charge without acceleration, against the electric field presend due to the given charge. So, as it says that there will be no acceleration, does it imply that...

Homework Statement **The book I'm working from doesn't have solutions for even numbered problems and the two problems I'm about to show you guys are even, so if you guys don't mind, I would just like to know if I have the right concept, or if I messed up anywhere. I wouldn't have a way of...

Hello World, These days, I'm trying to introduce the concept of waves into my stupid mind but It seems to be Hopeless..Whatever.. What are waves really?Can we see waves by any means in the world ?or they just do disturbance to the medium particles? Is there a real hope to understand waves...

Recently I've watched a few videos and read over some explanations of time dilation and am quite confused by several aspects. In the video I watched, the clock tracked time by a beam of light bouncing between two metal plates, incrementing one second per touch of the bottom plate. The path of...

What is the conceptual perspective of why equivalent capacitance is in parallel is more than the individual capacitance? (assume we have a parallel network of capacitors of equal value) I know the formulae, decoded the concept behind the eq cap in series but couldn't make any sense out of the...

I'd like to clarify my concepts about how a electron probability wave works. For a light wave, we can say that there is a destructive interference produced as and when the trough coincides with the crest of suitable amplitude. But since there can't be negative probabilities, how can there be a...

Greetings, I recently joined this forum to get some feedback on this project I'm working and which I have searched for an answer without any luck. My goal is to get the most airflow velocity in an outlet of a ducted fan. I'm using a 20,000RMP fan that is pushing air from a ~1.25" inlet to...

Suppose 5% of the Flash-Disk manufactured by a company is faulty. If we take, 100 flash-Disk how many are expected to be faulty? It must be 5, right? If we take 100 flash-Disk, what is the probability that 5 of them are faulty? This is what bugging me. We know 5% are most likely to be...

Some may already be aware of this but I discovered it for the first time today- http://www.spaceref.com/news/viewsr.html?pid=36068 http://en.wikipedia.org/wiki/Nautilus-X Looks like they may be testing the centrifuge on the ISS some time in 2013.

Hey, I am making a cooling system using a peltier junction with a cold finger on one side and a heat sink on the other. For my heat sink, I am depositing the heat into the phase change of a bismuth alloy (about 70 deg C). When the current across the peltier is increased and the hot side...

Hi, I have a question relating to the image below. http://img830.imageshack.us/img830/2173/elec.png/ From step 2 to 3, I get how 120V becomes 20mA but how is the 6k ohms affected? Why is it reduced to 3k ohms? And from step 1 to step 2, why isn't it like below? Case 2b instead of 2a...

This occurred to me when I first heard of the Space Time Frame Drag effect, which was confirmed by the results of Gravity Probe B (GP-B). http://science.nasa.gov/science-news/science-at-nasa/2011/04may_epic/" I am not a scientist or a mathematician, so I turn to my fellow humans who are. Do...

Homework Statement This problem is from Modern Physics by Kenneth Krane 2nd ED The problem is: An atom of mass m moving in the x direction with speed v collides elastically with an atom of mass 3m at rest. After the collision the first atom moves in the y direction. Find the direction of...

Homework Statement Hello Everyone! I am solving a lots and lots of questions on Mole Concept but i am getting stuck in this:- Calculate the volume occupied by 5.25g of nitrogen at 26\circ C and 74.2 cm of pressure. The Attempt at a Solution I actually don't know from where should i...

I have a few questions about decomposing partial fractions. I know how to solve these problems, but I just don't understand why I'm doing some of the things. 1. Why does equating coefficients work? I don't understand the idea behind it. 2. When you are decomposing fractions into constants...

Homework Statement http://enjoy.phy.ntnu.edu.tw/data/458/www/simulations/sims5326.html?sim=John_Travoltage#ideas" Hi, I am new here and I am taking Electro physics over at the University of Tennessee. I don't know how to integrate yet and i realized that i would need some help with this...

If an object is undergoing uniform circular motion then the torque of the object is zero. this i'snt a homework question but I'm just trying to understand this concept and why this is. can anyone give me a good definition of torque?

http://www.weburbia.com/physics/mass.html If it is not wrong, why not go about setting it straight and making it clear? Are we going to totally ignore the physical implications of having a relativistic mass, such as its dependence on the work done on the body relative to a given inertial...

Homework Statement v(t) = (-2 / (1 + 2t)) + 2 I must find the antiderivative s(t) such that s(0) = 5. The Attempt at a Solution u = 1 + 2t du/dt = 2 dt = du/2 √(-2 / (1 + 2t dt)) + 2 =√(-2u^-1 du/2) + 2 =√(-u^-1 du) + 2 = -ln|1+2t| + 2t + C At t = 0 -ln(1 +...

Can someone please explain this concept for me? As I understand it, you have a, let's say, a three-level atom with two hyperfine states and an excited state. Then you apply a pump source (perhaps a laser) to transfer the atom from one of the hyperfine states (say |g1>) to the excited state...

Homework Statement An oil drop whose mass is 3.30x10-15kg moves at a constant speed of 1.70m/s upward between two horizontal parallel plates. The plates are 1.00cm apart and are connected to a 6.75x102V battery. If the oil drop is negative and the top plate is positive, calculate the number of...

I've been debating with myself on a certain question. For example, Two blocks. Block A has mass M and the other Block was .5M or M/2 is pushed from rest with force F at a constant rate. (Let's say a hand pushing them for a period of time). There is friction on the surface. Block B...

Anyone can briefly tell me about this concept? Did it is a undeformable model?

Heres a simple situation I can't seem to adequately explain to students. A box experiences a force exerted on it by the earth. The third law of Newton states that an object that feels a force exerts an equal and opposite force, which is the force that the box exerts onto the earth. If the box...

Homework Statement We are looking at gravitational field intensity in particular here, and using the Earth as an example. The question states: Calculate the gravitational field intensity at a height of 300.0 km from Earth's surface. Why is it that: Since the point in question is outside of...

I have posted this here for two reasons, one I think you all will really appreciate this as a teaching tool to hopefully increase your students understanding (and hopefully grades) & second because you all might find/make more concept maps on more advanced topics or with focus shifted in a...

Homework Statement Take the Earth for instance, if I were to draw field lines, would it be field lines coming out of the mass or into the mass? I initially thought it would be going out because we could look at it as a "positive charge", but then I thought that was silly because gravity is...

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} =...