Works Definition and 435 Threads

AFAIK, boric acid is most commonly sold as a roach killer, although apparently it has many other more benign uses. I happen to know that it works pretty well on common fungi that appear around sweaty human joints. Wikipedia says it's used to control uranium fission in nuclear plants. Has...

i was searching for maglev on internet for my school science projects and i found this http://www.youtube.com/watch?v=rrRG38WpkTQ" on youtube which i thought i was actually looking for it. i know that maglev is based on repulsion of poles but how to keep our magnet to construct that type of...

What is Charge? "Electron has -ve charge,proton has +ve charge,neutron has no charge." But actually what is charge? "unlike charges attracts each other" Do +ve charge attract -ve charge to itself or -ve charge attract +ve charge to itself?

What are the top 10 physics and mathematics works of all time? I would definitely put Newton's Principia, Euclid's Elements, Galileo's Discourses, Einstein's On the Electrodynamics of Moving Bodies, etc., on the list, but what else?

Iv'e scene the documentary about string theory and i just have a few questions about it.(laymen terms) : 1.How does string theory contribute to a unified field theory? 2.Is matter really made of "vibrationg strings"? 3.What does string theory actually mean or what has been the impact...

Homework Statement y\prime=4x^3+6x^2+2x+1 Homework Equations The Attempt at a Solution 4x^3+6x^2+2x+1 -1 = 2x(2x^2+3x+1) (I moved the +1 over so I don't get 1/x, but I figured this should screw up the equation since it is no longer 0 on the left hand side.) -1 = 2x(2x+1)(x+1) So the...

I was thinking about looking at getting a minor in another branch of study and I don't really understand what this means in regards to your overall education. Whenever I try to research minor degrees I either find a website that tries to sell me one or a site that assumes you already know what...

How are parachutes like this made work: http://dolloutfits.com/vs/23.jpg Why do the parachutes remain on the sides nicely instead of colliding in the middle?

How does my 'average mileage' meter work? When I reset it, it starts averaging right away, so the first few miles have a big impact on the value. But after a hundred miles, each mile (including those first few) has a tiny impact (1/100th), right? If my driving habits change, these changes...

Not exactly a homework problem, but I'm trying to make sure I understand how the coefficient of static friction works. Given an object on an inclined plane and a question which asks for the minimum angle at which the object will begin to slide, I know that the formula to use is: mg...

I wonder how does Lloyd's mirror works, how does it produce the interference pattern? I look for many textbook, but all of them only tells the result and the setup without telling how to get the fringe and how to get the fringe separation. Anyone show me some hint or recommend me a book about...

Hi Iwant some inormation about atomic time.Can you help me?

I don't quite understand why cyclic rule works (from Pchem) (del x/ del y)_z = part of x with respect to y, hold z constant I don't know why is it negative 1? del x/ del y)_z * del y/ del z)_x * del z/ del x)_y = -1

Alessandro Volta uses a bimetallic strip (silver and tin) dipped in moist conductor (salty water) to make a battery. how can a potential difference occur between the two strips? in modern AA batteries, what do we use for the two dissimilar metals and the moist conductor?

Hi, Can any expert advice if I can control the DC motor to make it work as a stepper motor? I am using PLC to control the DC motor clockwise and counterclockwise in steps. Output O:1/0 controlling clockwise and O:1/1 controlling counterclocewise.I will use the timer say 0.5s pulse to...

(Update -- please read the third post -- I guess I'm wondering how an antenna works in particular).Hey, I can't seem to find much information on how the actually transmitting portion of a transmitter works -- how does one efficiently generate EM waves? Thanks!(I'm aware that the rough idea is...

I learned how circular polarization works way back in electricity and magnetism, I also learned how gratings worked. I recently watched a movie through circular polarized glasses which I had never heard of, nor can I find any information online including RealD's website (the company that uses...

Homework Statement I need to verify a couple of unknown forces in a truss, attached image (all individual trusses are 300mm in length) Homework Equations Determine the forces in trusses shown. The Attempt at a Solution This is a lab and I've used a telescopic gauge with a...

hello We are currently doing a TIPE Project on our first year of Prepa ( http://en.wikipedia.org/wiki/Classe_Pr%C3%A9paratoire_aux_Grandes_%C3%89coles ) We are thinking of doing our project on DVD/CD's (The theme is Surfaces), we would need to explain with precision how the encryption is made...

Looking for a connection to astronomy for a history of mathematics report on 19th century mathematicians. I don't do astronomy. Would like to know of any mathematical developments of Riemann that are used in astronomy that I can understand (which expressly excludes any thing with the word tensor...

I am making a circuit of a car toy. Actually, i have already done its first step. The next step i want to make a one which is able to reverse and i think i will need an amplifier which can work in both biases (foward and reverse). So do exist amplifiers that can work in reverse as well as in...

Im having trouble understanding how capacitors store energy. If a potential difference is applied to two parallel plates each with +-Q, it will set up polarisation charges on the dieletric between, which reduces the electric field inside the material. The potential difference between the plates...

Could someone give me a good explanation as to how superconductivity works. Feel free to be very technical. Thanks :smile:

I have said that many times. "It's 200x, does anyone make a stapler that actually staples most of the time?" It is something that aggravates the hell out of me. Pulling out failed staples. I have tossed many Swinglines in the garbage after they get below 90%. And since they don't start at 100%...

Homework Statement Hi, I'm taking AP Physics in high school, and the explanation I wrote is based on a demo in class, something like this picture: When the wheel is spinning, there is an angular momentum facing away from the string along the axis of rotation of the wheel. The gravitational...

Recently I've gained interest in reading the classical works of mathematicians and physicists and came to the realization that knowing Latin would be of great use. Is it worth the effort to learn the basics necessary to comprehend for example Gauss' works, or might I just as well get the...

Homework Statement Why is an 'I' beam good at supporting loads? (Bear in mind that I'm only 16, so I haven't met moments of inertia or anything like that, but have met basic calculus) The Attempt at a Solution Here's what I think so far. When a weight is placed on an I beam, the vertical part...

While I understand how coordinates work, I'm still trying to figure out how the last part relative to the azimuthal angle works, for example, in Minkowski metric- c^2 {d \tau}^{2} = c^2 dt^2 - dr^2 - r^2\left(d\theta^2 + \sin^2\theta \, d\phi^2\right) while I get that \sin^2\theta produces a...

Phone No Dial Tone DSL Works? Hi I am new to the forum and found you by googling my problem and found someone named Ray on the forum who had something similar happen a few years ago but not the same. Here is the issue: Phone works outside the house plugged into the box. Phone doesn't work...

hallo all, I was reading some information on my new set of earprotectors and I noticed it said that it is very good against high tones, high frequencies, but not for low ones. Why is this? How come you can stop high frequencies more accurate or faster then the low ones with the same...

How does the laser cooling work? I have read that it is used to cool ions in vacuum, by absorbing their kinetic energy with a laser beam; but I don't understand why the laser cool the ions and not raise their energy by moment transfer

Can someone explain to me how a false vacuum works? Thanks

How does a cathode heater work? Can't seem to find a straightforward explanation anywhere.

In general give a ranking from most to least of hours and effort needed for each occupation: Undergraduate, Grad student, Post doc, Lecturer, Associate professor, Professor. Also state the field you are referring to.

I want to know how our genes limits and define our growth, I mean, how the osteoblastos knows that they must stop or continue, how our cells knows when to stop growing or dividing, etc. Every human has a unique "morphology", the bones and skull has their own and particulary morphology, but...

Homework Statement IN microsoft works spread sheet how do you insert a inverse tan function. that is I know the opposite and adjacent side lengths but want to use the tan function to find the angle of a right angle triangle.Please help ,simple I know but I just can't work out how to do it...

Can I find classical works on Physics online somewhere?

does it have an ac or dc current? I think I still don't understand what is the difference between ac and dc. they both currents, both changing electric fields. (not static field since they are moving) they both creates a magnetic field. then what is the difference? (DC = steady...

http://www.woodencigars.com/vwftp.html I don't get it... my face was like O_O at the end of the video he uses e=mc^2 to explain how his "energy" goes into produce "mass". But can it be explained from a more mathematical/geometrical perspective too?

Wind power is a force of nature and it has been used for centuries like for Dutch Windmills. Permanet magnets are a force of nature which through innovation have now been produced so well that they can now hold up to 500 times their own weight. That is a lot of power. The only...

I'm sorry if you guys discuss this already but I need some clarification. The more I find out about this topic the more puzzling it becomes. Straighten this out for me. Thx 1) Does it actually works in vaccum? Many say yes and few say no. 2) When Beifeld and Brown did the experiment, they...

With (hand shake) agreements. http://www.newsdaily.com/stories/n02498013-americanairlines-faa/

Homework Statement A voltmeter with resistance R_V is connected across the terminals of a battery of emf EMF and internal resistance r. Find the potential difference V_meter measured by the voltmeter. Homework Equations v=IR Vab= Va -Vb The Attempt at a Solution tried using...

I hope someone here can help me with this. I have only one phone line at home,Verizon landline, with a regular phone connected to a wall, and a panasonic cordless 5.8ghz phone with extra handset. Everything works fine 95% percent of the time but 3 times in the last month when I wake up in the...

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_...

[FONT="Comic Sans MS"]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! [SIZE="4"]Contest Rules: 1. Any digital photo or digitally-scanned...

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...