Approach Definition and 545 Threads

A K+ ion and a Cl- ion are directly across from each other on opposite sides of a membrane 7.9 nm thick. What is the electric force on the K+ ion due to the Cl- ion? Ignore the presence of other charges. _____N Thanks, Matt

A Geometric Approach to the Standard Model Greg Trayling, Dept of Phys, U. Windsor, Windsor, Ontario A geometric approach to the standard model of the Clifford algebra \mathcal{CL}_7 is advanced. The gauge symmetries and charge assignments of the fundamental fermions are seen to arise from a...

Hello everyone, I was wondering what the easiest approach would be to do this: Find values of k for which the matrix system Ax = b, has a) no solutions, b) infintie solutions, and c) a unique solution: A = 1 1 2 1 2 -3 7 17 k b = 1 -3 32 I remeber doing a homework problem that...

Hi all, could you help me how to solve this limit? \lim_{x \rightarrow \infty} \left( 1 + 10^{-x}\right)^\left(10^x\right) Common adjustments for log involving the limit log (1)/0 don't work and no other idea comes to my mind... Thank you for any help.

Opinions on this one? Specifically for the QM uninitiated. If you have other recommendations for better clarity, please comment. Thx. A.

y''=-e^{-2y} Second order, homogenous, nonlinear. I think.

This new paper by Fay Dowker is a wonderful introduction to the whole field of causal sets, how they may said to approximate GR, how to make them covariant, a new approach to quantizing, the current state of play, and challenges remaining from a frequent contributer to the field. All in...

hey, these problems are for my physics 201 class and i understand what's goin on somewhat i just need help in my approach to the problems. They have to do with one and two dimensional motion and vectors. #1 A rock is dropped from rest into a well. The sound of the splash is actually...

Assuming you have the time of course, Would you guys favor homeschooling as an approach to a child's education? Is there more risk involved, albeit with greater academic opportunity?

let,s suppose we have a particle with mass m\rightarrow\infty then my question is if would be fair to make the WKB approach by setting the solution of the Schroedinguer equation as \phi=e^{iS/\hbar} wiht S hte classical action satisfying the equation: (dS/sx)^{2}+2m(V(x)-E_{n})=0 with E_n...

I have studied statistical mechanics using F. Reif's book, and learned a lot, but there are still a couple very fundamental questions which still elude me. If anyone would be willing to share some insight, I would really appreciate it! So Reif early on discusses the fundamental postulate of...

Any way to approach her! Guys i have a beautiful GND!(Girl Next Door!) She is tall and very attractive! :smile: The point is i have started liking her and she is about 5 years elder to me! Well the problem is there are already 4/5 guys who are after her and are just abt. her age! :cry...

how does weierstrass' approach to analysis differ from the classical approach, i.e leibnizs' and Newton's calculus?

what method do i employ to solve this? y''' + 4y'' + 4y'=0 does the above lead to something like this? r^3 +4r^2 +4r=0

I need to convert mol/cm3 into ppmv how would i go about that if i know pressure and temperature ? any leads ?

Certainly an easy question for you (specialists on this forum) but absolutely not clear for me. The ADM Approach (1 + 3), as it can be seen in Misner Thorne and Wheeler or some other reference, is based on a kind of extension of the Pythagorras Theorem to a Minkowki space. Ok. Its signature...

any isolated macroscopic system, like a large group of atoms, always tends to reach a state that has the maxium entropy. if the electrons in this group of atoms are excited, they will give out their energy so that more degrees of freedom are activated, hence the entropy of the whole system...

I'm creeping my way through DiffEq, and recently started reading Paul Dawkins' PDF, which is actually pretty helpful. He does, however, tend to assume that his readers know how to approach what he calls simple problems. Well, one of 'em has me stumped. 2t*y' + 4y = 3 I need to find the...

Kinda confused on this one becuase of the time difference involved A train leaves a station going south at 60 km/hr at 10:00. Another train heading due west reaches this station at 11:00. The latter train was traveling at 45km/hr. At what time are they the closest? To start with the 45...

A blue puck with a mass of 4.40*10^−2kg , sliding with a speed of 0.250m/s on a frictionless, horizontal air table, makes a perfectly elastic, head-on collision with a red puck with mass x, initially at rest. After the collision, the velocity of the blue puck is 5.00*10^−2m/s in the same...

After much much reading, I have come to the conclusion that the Bourbakist approach to writing textbooks is only useful for Algebra and Analysis, not for things like Dynamical Systems and Differential Geometry/Topology. Does anybody want to agree or disagree?

are there any physicists who are working at their university which specailizes in let's say string theory and in the same time are also working on the side on lqg? (or even vice versa). p.s sorry for the misleading title...

Hello folks, I found a lovely little book online called A Geometric Approach to Differential Forms by David Bachman on the LANL arXiv. I've always wanted to learn this subject, and so I did something that would force me to: I've agreed to advise 2 students as they study it in preparation...

I'm working on a problem that has to do with catalan numbers, and I'm just trying to figure out how to make a proof that shows what I am dealing with does in fact have to do with catalan numbers. I know this is very general, but I don't want someone to do my problem for me, I just want to...

The Quest for Consciousness: A Neurobiological Approach, by Christof Koch "Product Description: Consciousness is one of science’s last great unsolved mysteries. How can the salty taste and crunchy texture of potato chips, the unmistakable smell of dogs after they have been in the rain, or...

I have to find out, whether this sum converges: \sum_{n = 2}^{+ \infty} n^{\alpha} \left( \log (n+1) - \log n \right)^4 So I rewrote it: \sum_{n = 2}^{+ \infty} n^{\alpha} \left( \log \left(1 + \frac{1}{n} \right) \right)^4 = \sum_{n = 2}^{+ \infty} n^{\alpha - 4} \left[...

Hi, During a review this question has popped up (not sure what unit) "Determine the exact value* ````5pi``````11pi sin ___ - cos ___ ````4`````` 6 I am not sure what to do with the sin and cos? Thanks

i am looking to learn calculus. i will take it in college for i wish to major in physics but i thought it would be helpful to learn it now, plus i think it will help with my independent physics reading and whatnot. i also think it will be cool in itself. anyways, i am considering getting...

Hi all, my task is to solve the convergence of the sum in dependence to the parameter a real. \sum_{n=1}^{\infty} \frac{a^{n}}{1+a^{n}} I did it this way: First I found out that if the sum converges, a will have to be in interval (-1, 1). So how to prove that for these values of...

Let f be a function satisfying f'(x) = -3xf(x), f(1) = 4 and lim x->infinity f(x) = 0. Evaluate integral of -3x*f(x)*dx between 1 and infinity. Does this have to do with using comparison properties or something? I really don't know where to start. Thanks for any help.

this problem is in the improper integrals section but i just need help taking the integral. the bounds are from 0 to positive infinity. xarctanx/(1+x^2)^2 i tried doing a trig sub x = tan θ, which gives θtanθ/(secθ)^2 I believe, which gives θsinθ/(cosθ)^3. I couldn't find anything to help...

This is a chess/math puzzle I invented: Consider a fully set up chess board (in starting position). Invent a condition (new rule) in which black wins without either side making any moves. Note: this problem has a really abstract and *topological* approach. :smile: Please email me...

If F(x) -64/x^2 and it wants me to find an equation that decribes its position at (8,-1) which way do you think is best to find this out using the division of deritives or get it by limts

The following is a discussion paper I wrote some time ago. It suggests a change in attitude to the treatment and possible therapies available for persons suffering mental Illnesses. At first glance it may appear to be rather radical but actually it is quite conservative. Cognitive behaviour...

Antisymmetric tensors combine with symmetric tensors to give the thermodynamic arrow of time, which is really a continual densification of spacelike surfaces? More random thoughts on the unified field theory: symmetric tensor: A^uv = A^vu antisymmetric tensor: A^uv = -A^vu...

any comment on an approach to quantum gravity tried by Stephen Hawking, I think in the 1980s and 1990s, but apparently abandoned? It was called "euclidean quantum gravity" and involved a sum over spacetimes somewhat analogous to a feynmann path integral---a spacetime being like a path. In...

Hi, I'm trying to do a problem that goes something like this: There is a mass (m) attached to one end of a massless rod (length l). The other end of the rod is attached to a frictionless pivot. The rod is released from rest at an angle F0 < pi/2. At what angle F does the force in the rod...

Such as sqrt 5: (2.236067977...) Start with the fractional seeds 2/1, 9/4,... New members are generated (both numerators and denominators) by the rule new member = 4 times the current plus the previous. Which generates the progrssion 2/1, 9/4, 38/17, 161/72, 682/305, 2889/1292...

Hi, Can somebody drill me on the "congruences and modular arithmetic"? I know it is a big topic, but I think I am missing "something" in my knowledge... These things seem very unusual to me, and makes no sense sometimes. Find smallest integer n, where: 3^n \equiv 1 (mod 7) Is there a...

arXiv:gr-qc/0401102 v1 26 Jan 2004 A New Approach in Quantum Gravity and its Cosmological Implications Simone Mercuri Giovanni Montani ICRA—International Center for Relativistic Astrophysics Dipartimento di Fisica (G9), Universit` a di Roma, “La Sapienza”, Piazzale Aldo Moro 5...

Just out: http://il.arxiv.org/abs/gr-qc/0401102

Particles having nonzero rest mass can approach, but not reach, the speed of light, since their mass would become infinite at that speed. Can anyone expound upon this commencing with the very fundamental concepts (nonzero rest mass, mass, inertia, infinite mass etc.)?

Hi all, I came across a problem on collisions on one of my professors old exams. The problem is: http://home.comcast.net/~msharma15/problem_2.jpg The way I am trying to approach it is by applying the conservation of linear momentum and energy, but the problem is that I still get left...

I was wondering if two electrons were to approach each other, and if we regard electron as having wave-like properties, then, there is a chance that destructive interference will occur, which translates to the destruction of both electrons!?

I have recently listened to the tapes of the "Journey through the Tenth Dimension" lecture, given by Michio Kaku in 1989 (I think). He gave his idea of why we haven't found intelligent, extra terrestrial life. He used an illustration of an ant-hill. If you see an ant-hill, do you feel...