Works Definition and 447 Threads

Some examples in textbook make me confused when these two works are discussed at the same time. One of the works is the (mechanical) work in work-energy theorem: \Delta K = \sum_iW_i, where K is the kinetic energy and W_i was the work done by the i-th force. The other is the...

Just curious. For some odd reason, I don't seem to get it.

Homework Statement What technique should I use to evaluate: \int_0^L \frac{1}{(x^2+z^2)^{3/2}} dx Is there a u-substitution that works?Homework Equations The Attempt at a Solution

As GeorginaS said in the thread, this is going to a challenge to selected just one picture for this contest. Everyone one of them is gorgeous. Still, you will have to select one that best represents our theme, which is on water as the main subject. Good luck to all! 1. _Mayday_...

Water Works This week, your picture must contain water as the main subject. This can be out of a tap, in a glass, in a river, in lakes, or coming down from the sky. It is water, water, everywhere! Contest Rules: 1. Any digital photo or digitally-scanned photo relevant to the theme will...

Homework Statement I have to find for which values of x the following converge Homework Equations \sum n x^{n} \sum \frac{x^{n}}{n} \sum n^{n} x^{x} The Attempt at a Solution I used the ratio test for the first two and the root test for the last and found respectively that...

I would like to read the original works of mathematicians and physicists. I am in the second year of maths & physics. I was wondering if this would be any good for me. Also, how would I go about finding their works? It's not as though the originals are published, it's mostly second hand stuff...

A new solar technology based on tiny nano-sized antennae is capable of harvesting energy with 80% efficiency, as opposed to the 10-20% seen on commercial solar panels today. But if that isn't amazing enough for you, these new panels can even harvest energy at night, by absorbing light from the...

I have magnet wire and I have steel with extremely high iron content. I was just wondering, if I were using the same amount of wire and metal no matter how I built it and I were just making a straight cylindrical electromagnet, what would be the more powerful design? More towards the short and...

I'm in need of some help here regarding works on the lives and thought of Copernicus and Galileo. Specifically I'm looking for books that would survey each of their contributions to science while also devoting a similar amount of time to how each of them influenced scientific inquiry at that...

Thermocouple-Uses and how it Works? Homework Statement I need to investigate how current in a diode varies with extreme temperatures. I have no idea how to do this but could a thermocouple somehow be incorporated into the investigation. Homework Equations Can a thermocouple be used to...

The standard explanation, for why some materials are conductors, and some are insulators, is that they have different band structure. An insulator has only the valence band filled, and no electrons on the conduction band. An conductor instead has electrons also on the conduction band. The...

Hi, I have a newbie question regarding caps in series and parallel. When you apply voltage to a cap in a circuit, is there a difference in the voltage on the other side of the cap between the methods of use above? Like a cap in series, does it need to be charged fully for the voltage to be...

DSL works - No Telephone Dial Tone?!? I noticed a few threads concerning this problem and as I'm thoroughly beyond annoyed with Verizon, I thought I would lay my problem before those of you with some smarts - as opposed to the company's technician with half a brain cell. For a year, my phone...

Hi all. I am finding information about liquid dispensing system. I got the following website: http://www.ijfisnar.com/dispensers_jb1113.htm I would hope to know how the syringe is "pressed" to dose the liquid inside the syringe? Do you think this system can provide a steady flow rate?

Homework Statement Show divergence theorem works For the vector field E = \hat{r}10e^{-r}-\hat{z}3z Homework Equations \int_{v}\nabla \cdot E dv = \oint_{s} E \cdot ds The Attempt at a Solution \nabla \cdot E = 1/r \frac{d}{dr}(rAr)+1/r\frac{dA\phi}{d\phi}+\frac{dAz}{dz}...

Homework Statement My book says that \epsilon \vec{n} \times \vec{q} represents a small rotation about q. n is an normal vectors Obviously the cross product is orthogonal to both n and q, but I did not know it corresponded to an angle? BY the way, how do you make a cross product in tex...

can anybody focus something on how pipes in parallel will work in comparison to the same pipes in series.i want to calculate pressure drop across 4 parallel pipes emerging from a tank & entering inside the other tank . pipes of sam dia,& same length. thnks

http://news.yahoo.com/s/ap/20070730/ap_on_sc/hollywood_pigeons;_ylt=Aps05PxEaRMwQ1_iWqisBBCs0NUE I wonder if there is a similar way, that can be cheaply produced, to control rats/mice as well?

Hey surely you guys have heard of the x-zylo toy? Its a toy that has been known to fly 200+ yards. If you don't know about about it, do a google search on it. How does it work?

I was trying to find the orginal works of laplace and grassman, but could not find them. Well I found some on amazon but they were permanently out of stock. So I ask you, where in the world can I find them? Also are there any other good texts that you'd liek to recommend(I speak fluent french)?

It Works! Muahahahaha~ I have to do a project for my controls lab course. I decided to do the stabilization of an airplane in pitch. I wanted to make something that would actually attach to one of my RC airplanes, but the problem is that I’m not an EE and I don’t know/have the time to build and...

Hi! I've just bought a fish finder and while playing around with it, it turns out that it isn't much good in shallow water. Now I'd guess it's using ultrasound as it can operate at depths up to several hundred feet and I presume therefore is getting far too much ground penetration at shallow...

hola, first of. I am not mentally gifted enough to understand math involving letters so if you got a response to the following thread please make it in laymans terms. The invension?... more like an idea. would it be possible to make a double keel hull. (like a catamaran) that would be...

I was wondering,how does positive feedback works in opamp circuits?Like is there any formula for calculating positive feedback?I know that with negative feedback we have Vp=Vn but I don't know how it works with positive feedback!Thanks for the reply!

Could a book craftily cobbled from thousands of documents over thousands of years (otherwise randomly) show what might first appear as prophecy?

I Have two set of Qs i worked throu. & i am not sure of my works am i on the right tuck

Could anyone give me a brief explanation of how a capacitor works? What does its I-V graph look like? Thanks

I'm currently building my CV...I have 2 published papers, and 2 unpublished papers. I'm curious if there's an official term I should be using for the unpublished papers...they are complete and have been submitted to a conference, but will not appear for a couple months. I've seen "Under Review,"...

Hello everyone! THe directions are the following: Carefully formulate the negations of each of the statements. Then prove each statement by contradiction. Here is the problem: If a and b are rational numbers, b!=0, and r is an irrational number, then a+br is irrational. I made it...

After the news yesterday of British, Pakistani and US surveillance thwarting a terrorist plot that would have killed thousands of innocent men, women, and children. How do you feel about surveillance now? Here is a good op-ed piece that basically recaps what happened and also reminds us of...

I'm sure we've all heard of The Works Toilet Bowl Cleaner (Hydrochloric Acid is what the guy on the phone said, but the bottle said Hydrogen Chloride, you guys should know. :) ) and Aluminum. I know that the Acid has a negative or positive Hydrogen ion, and that the aluminum liberates the ion. I...

How the Greenhouse Gas Effect Works We all know by now that the greenhouse gas effect depends upon absorption by greenhouse gas molecules of infrared energy radiated from the Earth’s surface, and which is then re-radiated by these molecules in all directions. Effectively, half the energy is...

It's a good thing that Evo doesn't have to cut this tree down.

How exactly does it work?

At my company, we have a design using thermoelectric cooling. I have no idea how they work, is there some phenomenon i don't know about?

with the help of an oscillator you create a frequency but how exactly do you insert the electric signal you've gained from a microphone into that frequency? if i understood the microphone right it transfers the vibrations into electrical form by altering let's say the current so that different...

I searched the forum, but I couldn't find the answer to my question. And sorry if this is in the wrong thread. But anyway. I understand how a parsec works, when it comes to the simple trig behind it. But how do astronomers work out the angle opposite the radius of the Earth's orbit around the...

hi all (hopefully friendly) people... In my year 12 physics class, i have been given a report on AC induction motors to complete. Basically the requirement is the explain the physics behind it, how it works, why, etc Can someone give me a list of things that i should cover as i am...

hey all, so we all know bio diesel works, and I am guessing that most of us know what it is and even how to (basicly) make it. you obviously have to use it in diesel engines, thus the name. This must mean that it has a low octane, high cetane make up. my question is, is it possible to just mix...

Would someone, PLEEEEAAAASSSEEE, explain here how holography actually works. ...I mean - I know (I've already read about it times and times again) - I know it has to do with interference patterns (interaction between two components of light (object and reference light)), I see it has to do...

Can someone explain to me how an induction stove works? I know it has something to do with magnetism, but how the casserole can get hot while the surface of the stove itself does not blows my mind! Anyone?

phone has no dial tone DSL WORKS OK?? my home phone has no dial tone but the DSL works fine no incomeing calls eathor I went out to the outside box and checked the connections no dial tone there eathor, but as you can see by this post I am on line! called [on the cell] the local bell system...

Hi...I am very interested in how sound works from the 'human perception' side of it. I want to know how different sounds and harmonics interact...for example, two noises making 50dB of sound each, we do not hear 100dB of sound, yet it is more than 50. I want to know how our ears and mind work...

Hey guys, I was reading on another forum when someone posted the following: I have no idea what to make of it As the posters here are much more qualified in the field of physics than I am, could someone please give me a sense of what the above says, or if it's even coherent? thanks...

can someone please explain how a digital to analog converter works if say your equipment includes a computer with a software like Labview, a Lab-NB board, a terminal block (USB) and an oscilloscope. what is each component doing and what is being transferred between them? thanks.

i would like to know how a cartesian diver works using mathematics. I have found how the diver works using words and explanation but not using equations and math. Please HELP!

Hi, I was woundering if somebody could explain to me using the equation ΔU = Q + W (The first law of thermodynamics) how a fridge works? what happens with a meteorite? what happens with a standard fan? Much appreciated -- Regards Jason_Hyde

How does this stuff works (CBR)

hello I just started learning physics and already am stuck Train starts moving with constant acceleration a . In five minutes it travels 5 kilometers . Find a ! S = a * t^2 / 2 a = 2 * S / t^2 My question is why does this formula work only if we express time in seconds ? If I...