Issues Definition and 429 Threads

Sorry for my bad English and mostly for my bad Physics. For me it doesn't make any sense regarding the expansion of the Universe as a distant process, a sort of time&space machine which 'degulfs' more room for the known things to occupy. My guess is the expansion is happening here now at a...

I am considering making a yagi antenna for a wifi adapter and I have been warned about some possible side effects that I wanted confirmed or disproved.. I read somewhere that the 2.4GHz band also is the resonant frequency of water and is used by microwave ovens, but at a more powerful rate...

Ok, I've already posted this same question in another forum section but probably it was the wrong one and the post was deleted, according to the rules. My apologies for the big mistake. Sorry. :approve: I try to re-post the same question here, hoping it is the most suited section. I'm...

Hi all, I hope that I'm posting in the right section of the forum. If not, I kindly request a moderator to move the thread to the proper section. Thanks in advance. I'm currently working on a prototype of a 3d simulator in which entities of different shape and mass move possibly colliding...

Homework Statement To save money you put $3000 at the end of each year in an annuity that pays 6.8% compounded annually. Use the formula for the value of an annuity. The Given Formula: A=P[(1+(r/n)nt)-1] ______________ (r/n) How much would be saved at the end of six years...

I have a system of three DE's and one other definition. The system I'm working with is given in the attached equations.nb. I've attempted two methods to solve the system. The first is by assuming steady states on the three DE's, setting them to zero, and using algebraic manipulation to...

Hi I'm trying to convert m3/hr to kg/hr for a steam system operating at 14.5 barg and 1150 deg C. I was planning on using steam tables to get the specific volume but anywhere i look the temperature seems too high to have any values. Any suggestions of places that do have the values I'm...

Homework Statement A force F1 of magnitude 6.00 units acts on an object at the origin in a direction of 30.0° above the positive x-axis (Fig. P3.10). A second force F2 of magnitude 5.00 units acts on the object in the direction of the positive y axis. Find graphically the magnitude and...

Hello, I am pretty new to programming at all and am having some issues with working out why this program is not compiling: Program MAIN DO J = 1, 11 K = 10 + J P = 0.4 !POSITION OF MAXIMUM CAMBER AT 40% CHORD! M = FLOAT (J + 1)* 0.01...

Hello, I am new to the TI-Titanium and have run into a few rather simple obstacles that are keeping me from answering physics questions in the correct way. First off, by typing: \sqrt(5) the answer comes out to: =\sqrt(5) as opposed to 2.2360... (I believe this is a setting/mode issue)...

So i have to had my central heating fixed 6 times, my loo 3 times, the problem is i have to go through an answering service every time, how does one nail the contractors?

What is the fundamental knowledge that the average, or above-average physicist must possess? Put simply, even a subject as rudimentary as undergraduate level classical mechanics teems with so many formulae and so many derivations that I find it incredibly mind-boggling that a physicist should...

I have been following the situation about the complaints against NRC Chairman Gregory Jaczko by the four NRC Commissioners. From what I have seen and heard, I would think that the complaints are legit considering the credentials of the commissioners and the fact two are Democrat and other two...

This emerged from random thoughts on a story about a victim of domestic violence: http://www.bbc.co.uk/news/world-asia-16201961 Human rights groups in Bangladesh have demanded a severe punishment for the husband of a young wife who allegedly cut off most of her right hand. I believe we never...

Homework Statement I think it runs up to the couts I have in my input function but then it just crashes. I'm running it on DevC++. The code is in [b]3 along with the assignment link. It's assignment 11 that I'm working on and the text file is next to the link for the assignment. I would...

Is anyone here experienced with NX7.5? I'm having some display issues and don't know how to tweak the video settings.

I'm sorry if this is a completely inappropriate place to post this in, but I know a number of people in this forum work or have worked in academia, and I was hoping that I might be able to get some advice. Also, since it is a physics professor specifically I'm having an issue with, I think it...

Homework Statement A particle of mass m is repelled from the origin by a force inversely proportional to the cube of its distance from the origin. Set up and solve the equations of motion if the particle is initially at rest at a distance x_0 from the origin. (This is one dimensional...

Hi everybody, I don't know if this thread is in the right place because it deals with a mix of world affairs and science. If I did post this in the wrong place, I do apologize. So my question is: Can Science be a way out of the troubles within the world today? I personally believe that...

Howdy! I'm looking for some opinions from you guys on what I should do with some troubles I am having in my chemistry class. The school I am attending has a very small, but good Physics program. The professors are top-notch and teach because they love teaching. I am choosing not to pursue...

Hi. I recently started studying differential equations, so bear with me. I started out with the following equation: y'' - 10y' -61y = xe^{-x} I know the method for solving these, but the thing I don't understand perhaps isn't the differential eq. part, rather the simplification of the...

I'm trying to make a program that prompts a user to enter a binary number and then converts the string into integers by using Integer.parseInt. Right now though, I'm having trouble with tokenizing the string. My code works when I use the predefined variable temp but not when I enter the same...

Origin of the Universe Stem Cell research Development of nuclear energy Our use of the Earth's resources and its impacts Man's growing need for energy and its impact What are the strength and weaknesses for these issues that have brought Science and Society into conflict?

I've picked up a bit more since my last problem. I need to solve the following DE: x^{2}\frac{dy}{dx}+x(x+2)y=e^{x} I decided to use variation of parameters, so I re-arranged it like so: \frac{dy}{dx}=\frac{e^{x}}{x^{2}}-(1+\frac{2}{x})y Then solved the homogenous DE...

First http://www.scientificamerican.com/article.cfm?id=splitting-time-from-space" THEN http://www.rense.com/general28/erin.htm" and NOW the super neutrino radiation evidence of faster - than - light motion. Should we have seen this coming? Also here's something I've always...

Currently there are clear indications that there is a strong case for a phenomenon of http://en.wikipedia.org/wiki/Peak_oil" . 1. The International Energy Egency, who was traditionally very conservative about it (and still is), recently admitted that it occurred in 2006 for conventional sources...

I am working on a problem trying to find out why a 0.010” orifice can be used to open a pilot actuated, spring return pneumatic 5/2 directional control (spool) valve, but a 0.0045” orifice only seems to work intermittently. The air system that I am working with is 100 psig. The air enters...

See post 2 in this thread, none of the latex lines are working now (they were working before), post 4 is slightly messed up: https://www.physicsforums.com/showthread.php?t=306442 In post 8 in this thread one of lines is messed up: https://www.physicsforums.com/showthread.php?t=360987...

I just can't figure out how you arrive at having a diagonal matrix consisting of Jordan blocks. Going by Lang, a vector is (A - λI)-cyclic with period n if (A - λI)ⁿv = 0, for some n ∈ℕ. It can be proven that v, (A - λI)v, ..., (A - λI)ⁿ⁻¹ are linearly independent, & so {v, (A - λI)v, ...

A second is measured thus: "the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium atom." What if the cesium atom itself is moving close to the speed of light? Would that not change the time...

Hi any idea what is the most relevant website to find out OrCAD PSpice ebooks, application notes and tutorials and how to resolve its convergence issues in Switch Mode Power Supplies simultions. Please be precise and quick. :cool:

I had issues with dandruff for a long time. Once my second kid was born, I went two weeks without a shower. My dandruff basically went away. Since then I've been showering with water only. My hair has become way healthier and my skin is all a consistent color and doesn't get scraped and...

I am trying to build the instrument according to this link http://www.inventgeek.com/2009-Projects/Laser-Instrument/page5.aspx I am having problems with lasers.I can not focus the laser dot on the photoresistor.So I thought about laser array(fabricated)but i could not find it.So I am now...

Greetings I have been trying to find the orbit of Mercury using the geodesic equations with the Schwarzschild Metric, more precisely I have been using the equations derived in "General Relativity, An Introduction for Physicists" by M.P. Hobson, etc, that is: <math>\left(1-\frac{2\mu}{r}\right)...

Hi all, The question is: Given that X follows a geometric distribution, prove that P(X>j+k | X>k) = P(X>j). So this is all I have: P(X>k+j) = (1-p)^k+j, (a proof covered in the text)...

I have third (and final) round of interviews scheduled for next week with Qualcomm. The Qualcomm job is full-time, and in Colorado. In short, it's my dream job. Medtronic has been calling me and asking if I am interested in a job opportunity there, a contractor position which is less...

So in Griffith's (ed. 2 page 37) there's an equation that says that **pretend the h's are h-bars...I don't know Latex very well** ih\frac{1}{\varphi}\frac{d\varphi}{dt}=-\frac{h^{2}}{2m}\frac{1}{\psi}\frac{d^{2}\psi}{dx^{2}}+V Since in this simplified case V where is a function of x alone...

The problem is we don't know if it's a real floating box design. I have tried to find out information about Fukushima I foundation type but hasn't been able to find it. Anybody else luckier? Just because there is a thick bottom concrete doesn't make it a floating box. If it's a floating box...

I was walking down the hallway at work and saw a poster. Someone must have put it up outside their office. It said that falling asleep with the TV on reduces the bodies production of melatonin. So I looked it up and found an interesting article on Discovery.com...

Hi, I'm trying to enter a spacetime with makeg(spacetime_name): on GRTensor II. I'm just following the simple example in the documentation, but instead of doing what it's supposed to (e.g presenting me with text offering me certain options and then me selecting say option 1-4) and presenting...

There was an article in my local newspaper about CFL health issues so I googled for its international source. I came up with this Edit: innapropriate lisource deleted Should I replace back my house's CFL with incandescent?

Dear All, I am plotting a density and a contour plot of the same function in order to have a smooth shading in the background of the contour lines. I do this using "Show[DensityPlot[...], ContourPlot[..., ContourShading->None]", like the following example given by Mathematica help files...

Dear All, I am using gnuplot to make plots from data files generated using a fortran program. Those data files are basically big lists of 3d coordinates, just like like (not my real data, just an example): 10.0 1.00 0.01 20.0 1.00 0.14 ... So, when I use splot, I...

Hello, I was just wondering if anybody could give me any ideas about a possible direction in a Physics issues investigation. I am looking at choosing one around nuclear energy and the issues of radiation. Any help or interesting sugestions of avenues in nuclear physics, and or possibe guiding...

Homework Statement Simplify: 3c-(\frac{2a+c}{8}-\frac{a+2c}{4}) The Attempt at a Solution I got this: \frac{9c}{8} But the answer is: \frac{27c}{8} It's simply an issue with whether I find the LCM or I use this formula: \frac{a}{b}-\frac{e}{f}=\frac{a*f-b*e}{f*b} If...

Issues with Discrete Fourier Transform in Mathematica Maybe someone else had this problem. Lets say we have a sampled Gaussian pulse in time domain and transform it into frequency domain. For that I use the discrete Fourier transform. Now the resulting set of transformed values is made up of...

i have one problem for pumping treated water in line 4 bars there is no suitable pump with this suitable head so what is the procedures for series instlations ?

I have problems with my code.As a result of calculation I got rank2 l(21,1) array.Due to the THE ITERATIVE PROCESS I will get the same array in every iteration.How to allocate values and use them later.Should I create new array like do iter=1,n lbig(iter,nmax,1)=l(nmax,1)?

Question) A solid is formed by revolving the area inside x^(2/3)+y^(2/3)=a^(2/3), a>0; to the right of x=0 and above y=0 about the line x=a. Find the Volume of the solid using; A) The washer Method B) Cylindrical Shell Method I am at a loss at how to set up this problem...I understand how to do...

Hi all, I am working on a robotics problem and I have to get the determinant of a 3X3 matrix in symbolic form. The expressions are quite complex, Matlab 7.10.0 solves the expression in about 30 seconds but cannot display the answer. I would need to copy and paste this answer into another...