Practical Definition and 308 Threads

What would be the practical effects if it is proved that P=NP and an efficient polynomial time algorithm is found for NP-complete problems? By practical effects, I mean the practical effects of perfectly solving the problems which have been proven to be NP-complete (like Boolean SAT...

That is, entangling two particles and sending one off in a controlled manner (i'm not sure if we're sophisticated enough to even contain a particle in a quantum state without interference so please fill me in) to a black hole and then observing the entangled particle that we kept in some lab on...

what exactly is a quotient set? I know it "partitions" a large group of numbers into discrete subsets but I still don't know what exactly it is in practical terms. Like, does it relate somehow to Euler's phi function?

Is there any practical reason for calculating simultaneity of distant events? Two events either are causally connected or not, and there is nothing relative about this. If a cause-effect link doesn't exist, does it matter if the events are calculated to be simultaneous from a certain point of...

Homework Statement This isn't acctually a problem but I really don't know what to do. I was doing a simple activity about Hooke's Law during class today where I have to set up a apparatus and measure the extension of spring when when we put differnt masses on it. I didn't do it properly so I...

Homework Statement Design a lab experiment using a LDR to investigate how the intensity of light emmited by a lamp varies with wavelength Homework Equations how the wavelength of the light falling in the LDR is determined how a measure of the intensity can be obtained from the LDR...

[Urgent]On error analysis of my practical Homework Statement well, the aim of the practical is to calculate the speed of light using LED, oscilloscope and varying fiber optics cable. i have my results as follows : L /m t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 taverage 5.00 (28 30 28 28 28 28 28 28...

OK, so I'm writing a program and I want to calculate modular exponents. The only hard part is the multiplications. It would be best if I could work with numbers where, at all intermediate stages, each number is less than 2^64. If I must create a bit array I suppose I'll do that, but this would...

Following a few threads here, I would be interrested this question was clarified as much as possible: How is the absolute entropy defined, and why ? How can it be measured ? Is it needed for applications, and when ? (examples ?) Thanks to help clarify this fundation of thermodynamics...

I am having no luck with my writeup. We did two related practicals: shot a rocked straight up to find the height, and then shot out at angles to obtain a range. For the first one, two angles were obtained using a clinometre, then averaged: d = 30 θ = 60, 69 Av. θ = 64.5 d = 60 θ = 46...

Dear colleagues, Perhaps you can help me on this... :redface: I have two questions: 1) Is it possible to receive posts and comments from someone else's blogs via email (something like an rss to email converter)? 2) Is it possible to save videos from Perimeter Institute on the hard...

Not really a "help" question, but it is coursework related... now that the Physics A-level coursework and Practical Exam are over (so no chance of being accused of cheating), I'm curious to know: what did everybody think of them? All I can say is, there wasn't enough time. The spring question...

hello i really struggle with this! i can never get the equations right or anything! i can't find any sites that help! i have a practical exam tomorow that could be about it please help thanks

so the way book states it, for the sc. lemma to work, |f(z)| has to be less than or equal to 1 and and z has to be less than 1. However, the book seems to use the lemma in some problems even if one of the conditions is not satisfied ... any help with gretaly appreciated also ...if you could...

Probably this is already being disscused somewhere else, but nevertheless... --------------- I'm going to use some analogies to explain it. Human kind have found out and learned to use only sources of energy that are observable (expiriencable) by some/any of the human senses, or are...

Hi, I have a lab practical this Thursday evening, and I'm hoping maybe one of you guys can help me find the answers to these practice questions. These are some compiled questions from past labs that I need help with: (takes a big breath) I) What are the factors that need to be taken into...

just curious.

I need to approximate how much force is exerted on a 16cm diameter wheel (assume it's rigid and doesn't absorb force) upon traveling over an average sized bump (relative to its diameter). Does anyone have a suggestion on a method to do this?

anyone stuck for ideas?

If one is only considering the mechanics of a lever, what is the maximum a physically possible lever can lift ?

Hey can somebody list the practical applications of Modern Algebra? Anything that's grounded in reality?

Generally, what do IC Companies like Intel and IBM hire physicists for? Are they just looking to fill research positions or do we see them on the practical side?

Practical question about circuits and stuff. :D Maybe this is the wrong forum.. but I'm trying to do something... (Might be silly, but oh well..) I have this dance dance revolution (DDR) pad-- for those of you who don't know, it's that arcade game which everyone plays at arcades and stuff--...

Right, I'm about to open a big can of worms: I'm investigating eddy current damping of Simple Harmonic motion and I'm going to be investigating how the damping coefficient varies with various factors including the distance of the magnetic field (irrelevant, just informing). A "magnetic tunnel"...

I'm working on a problem that includes testing large numbers for primality. I'm using Pari/GP's built-in Baillie-PSW pseudoprimality test, but it (understandably!) runs slowly. I have some qustions, then: * I've been sieving the small prime factors from these numbers. For numbers if the...

Assuming the current anti-nuclear public/political climate remains in place and no new nuclear plant sites would be allowed (nor within a reasonable timeframe) why not just simply increase the existing capacity? For a hydro plant it makes sense there is only so much water that can be...

What habits and technology can we adopt to reduce personal energy consumption?

any tips on how to improve my practical skills in physics? something seems to always go wrong for me in physics practicals, I am fine in chemistry. even tho i have a whole year (once a week) on pracs i managed to end up with a C in it.

Does anyone, by chance, happen to have some good, practical references in the design and preparation of piping systems for use in pure oxygen service? My ASTM references are about as close to worthless as it can get. Thanks.

Scary "Practical Joke" I saw an old rusted refrigerator turned on its side, with its back facing me. On the up-facing right side of this appliance, in gray spray-paint stencil letters, the following words: God hates puppies. Here now I was thinking of the Stephen King novel, It, wherein...

Hi, I have a few 50 ohm loop antennas tuned to resonate at 13.56 MHz. (inductive RFID antenna). I would like to test one antenna´s influence on the other, so I think one approach is to connect one antenna directly to a signal generator. Do I have to design any matching circuit between the...

Does anyone know any practical uses for the number Phi? I have just read a book about it and I am wondering what else it can be used for. Such as in Electronics or mechanical engineering. Thanks! =-)

Has anyone ever played a practical joke on someone and the results didn't quite turn out like you planned? Well, many years ago this happened to me. When I was married in the 80's, I decided to play a seemingly harmless prank on my husband. It was on a Saturday and there was a movie playing in...

can anybody tell with equation,the practical applications of partial differential equation and ordinary differential equation. If it is in mechanical engineering statics etc will be helpful

There are two things related to using oscilloscopes that I am a bit fuzzy on for a practical lab exam I will take tomorrow morning: 1) Use the oscilloscope to determine the frequency of the square wave between terminals B and C of the test box. ( We will press and hold down the button on...

I used a white tray to work on for my antibiotics investigation. What is the tray called? :frown:

Hi all. I've come to realize there's a giant gap in my electrical engineering knowledge. I've studied plenty of math, physics, circuit analysis, and digital electronics but yet can't figure out how to troubleshoot consumer electronic devices or construct simple gadgets. When I open up a DVD...

I just did a semiconductors experiment involving the Hall effect and a doped germanium sample. The type of doping was determined from the Hall voltage using the sign of the recorded voltage and the sign of the bias current applied across the sample. Now, my question is what could be a...

I'm not sure on what I have to do for this practical. I have to develop a theory and choose certain equipment for me to perform the investigation and obtain results... only i don't know where to start. the aim is: Investigate how the amplitude of a pendulum formed by a magnet and thread...

Hello forum. I'm in abit of a mess. My high school physics class is in the process or doing individual investigations into an aspect of physics we are slightly familar with. I had planned out an experiment to do with sound, but last minute i was told another person was doing something...

Hi there,...this isn't homework..its more to my practical...anyways...from the attachment given..that is the first page of my practical guide...the problem is...on the procedure part...it asked me to plot a graph of lg temp againts t ...if i do so...how do i get the thermal conductivity of glass...

im having trouble filling in a table similar to this: FORCE X COMPONENT (N) Y COMPONENT (N) F1 F2 F3 SUM these are the results: when angle is 30 degrees f1 =0.5N f2 = 0.5N f3 = 1.0N when angle is 50 degrees f1=1.6N f2=1.3N f3=1.4N I used approx 100 grams on each vector...

I really enjoy math at school and am pretty good at it, and am thinking (if I survive my next few math courses) of going into math in university, but I don't really know what careers are available in math - what would some practical applications be (other than, er, accountants or something...

The space shuttle had thousands of tiles that were close to the ultimate insulators. Has anyone gotten to the point where they're not $1000s a pound yet? I was wondering if anyone has created a thermos bottle that you could put in a microwave for a reasonable price. Why can't they spin off...

This is a math problem, but requires a little preface. In my home I am going to replace the wall-to-wall carpeting with Pergo type flooring. This type of flooring is less than half the price of real hardwood planks. Each “fake” wood plank varies in width and length depending on the...

Is it concievable to build passenger, cargo and military aircrafts that run on something other than petroleum? I suspect electricity is out of the question because of the weight of batteries, but what about hydrogen? How does the the weight/energy ratio of hydrogen systems compare to that of...

Can someone give me an example of where the following types of gates should be of practical use? NOT OR AND Thanks!

Hi there, I need immediate help as my pratical exam is on next Monday [18/10/04] and I would greatly appricate if anyone can help me with my doubts. We all know that for physics practical, mostly likely we have to draw a graph to conclue our results. However, after ploting the correct points...

I'm looking through One Two Three...Infinity by George Gamow. After having explained length contraction with the example of two ships passing in space who each view the other as contracted he comments in a footnote: "Of course this is all a theoretical picture. Actually if two rocket ships...

Just wondering if anyone here is doing AS Level physics practical tomorrow?