Idea Definition and 811 Threads

Homework Statement Let A and B be any sets. 1: Prove A is the disjoint union of A\B and A intersect B. 2: Prove A U B is the disjoint union of A\B, A intersect B, and B\A. Homework Equations ? The Attempt at a Solution I understand most of the basic terminology used. I know disjoint...

Homework Statement A ball of mass M attached to a string of length L moves in a circle in a vertical plane as shown (picture of circle with a radius drawn L and M as a ball on the circle.) the tension at the top in the string is twice the weight of the ball. At the bottom the ball JUST clears...

The time machine idea ! I see lot of discussion going on time machines. there are different theories but none of them seems to be bringing any results. what exactly we are lacking in terms of achieving this. I think we have fairly enough good technology available atleast at atomic level...

I'm considering this for summer at my local university (it doesn't have summer I or summer II options). Is it possible to do dynamics and statics all at once? Thanks!

Hello I've just joined the forum and know very little about physics but I have a passionate interest in exploring ideas and I'm curious if there any advancements that are being carried out already in the transport field. I'd appreciate any feedback, good or bad. Cheers.

I have been trying to figure out historically how Force applied over a distance was found to be a conceptual breakthrough. I know about Joule and some others, and their thoughts on the idea of energy. But I cannot find out who or what people actually came up with the notion that Force applied...

Imagine a device that allows athletes with knee injuries (or anyone for that matter) to be able to walk, run, jump or play any type of sport without ever putting pressure on the knee. I would like to know what you think.

1. 1.5 moles of a monatomic ideal gas is enclosed at 314K. THe initial volume of the gas is 3m^3. The gas is comperssed isothermally to a final volume of 1m^3. How much heat is removed from the gas. So deltaU=0, Q=-W, So we have to know the area under the P-V curve, but how can we get...

Homework Statement A(n) 71.3 kg person throws a(n) 0.047 kg snowball forward with a ground speed of 45 m/s. A second person, of mass 64.7 kg, catches the snowball. Both people are on skates. The first person is initially moving forward with a speed of 2.28 m/s, and the second person is...

Hello. I've been kicking an idea around for a while, and can't decide if it is worth pursuing. The main idea was to simply provide indoor lighting both day and night. The more evolved idea is to combine several current technologies to provide indoor lighting, power, heat, refrigeration and pure...

Well right now I'm flip flopping between some majors that I would like to do. Yesterday, Nuclear Engineering popped in my head as a candidate (adding to the list). I thought about it more and more and I thought of some interesting predictions and reasons to go into it. I would like some of your...

keep in mind that the people that i am presenting to have no clue what calculus is and i want to show them how they use it in everyday life.

I was reading about Eisteins theories and had a question. If light can not escape the gravitational pull of a black hole, then assuming that the black hole accelerates (at a constant acceleration) all matter and energy into its event horizon, then if the gravitational pull overcomes the speed...

Homework Statement Find the principal value of i^2i Homework Equations principal value = Ln r + iArg(z) The Attempt at a Solution dont know how to start..

Physics Communication Idea - "Prove Me Wrong" I had an idea that i thought would be interesting to try. I have been wishing lately to make proposals of certain ideas I had about how certain things in the universe may work. I wanted a way to tell them to someone more knowledgeable than myself...

Homework Statement Peter and Paul bet one dollar each on each game. Each is willing to allow the other unlimited credit. Use a calculator to make a table showing, to four decimal places, for each of p = 1/10, 1/3, .49, .499, .501, .51, 2/3, 9/10 the probabilities that Peter is...

I need an idea for a final project for my computational physics course. The problem is that I've only had intro mechanics and intro E&M courses so far and I'm currently taking modern physics. It seems like any interesting projects would require more physics than I've had so far. I was...

Ok,so I am a bit of a noob so go easy on me! i was having a chat recently with my uncle (whos an astro physicist here in the UK) and although he didnt really give me the time of day because he's a busy guy,he said that my idea wasnt too far fetched but to come back to him when its got a bit more...

Hi all, My Undergraduate thesis requires me to design an ice making machine by modifying existing machines. I will appreciate your ideas on how I should go about it. Thanks in Advance! :smile:

Suppose that A is a real 2 x 2 matrix with one eigenvalue \lambda of multiplicity two. Show that the solution to the initial value problem y' = Ay with y(0) = v is given by y(t) = e^\lambdat [v + t(A - \lambdaI)v] Hint: Verify the result by direct substitution. Remember that (A - \lambdaI)^2 =...

helloo! i have an idea that I've been thinking of and i'd like to get some opinion of its validity. imagine 4 hydrogen balloons (like those used to carry weather instruments), arranged in a square with one balloon on each corner. imagine in the middle, suspended by cables below the balloons...

I came up with this idea for an experiment involving subatomic particles. I wanted to create a sort of "hurricane" with protons and neutrons. The neutrons would be stationary in the center (i guess you could call it the eye due to the lack of electrical charge) with the protons revolving around...

I am not talking about superstrings, but the idea of supersymmetry itself. Let me say what annoys me. I will put aside the advantages of it satisfying Coleman-Mandula theorem or solving the instabilities of the Higgs field, lorentz invariance or any other consistency that it satisfies in...

Blak oddark muttuma cantopole blajpherin spoatomy. Ok the above sentence is totaly meaningless but... What the idea of this is to find out why... <--- This means anything at all while the above does not. My idea is that you have less chance of misunderstanding me with the above like of...

This is the explanation I give people when they ask about time travel. I am only an undergrad so I just want to ask the more experienced people here if this is correct. Thanks... Time travel in the context of Einstein's relativity: So we all know that time travel into the future is easy...

When did windows users get an opportunity to request features for windows7? Why wasn't I told? Essentially isn't windows7 supposed to be vista that works? Even as a beta tester - it was to check its stability and find bugs. Not to add or remove features. So have we been had?

Idea of a "subsequence" I don't fully understand the idea of a "subsequence"... 1) Say we have an infinite sequence {an} = {1,2,3,4,...} Then if we only take {1,2,3} with FINITE number of elements, is it a subsequence of an? 2) If an is an infinite sequence, is an a subsequence of an...

Is my website a good idea? Im not going to explain the idea here because then i cannot be really sure if people on my website understand the idea. My website: http://mrlinkster.ning.com/ Thank you for any replys.

The safe usage and storage of Hydrogen gas H2 requires a decent level of purity- say above 98%. Those who have researched hydrogen production using electrolysis would be aware of several methods of separating out the small amounts of heavier gases like oxygen that are often present. Here is...

How common is it to have a final worth 100% of the course mark? Do you think it's a good idea? Why? Discuss.

So i was thinking, if you drop a ball that has a bouncy property to it, it will travel half as high after the bounce, then in theory it will bounce half as high, and half, and half, and half but never reaches zero this is not true in reality though, because there of a loss of energy due to...

Homework Statement A highway curve of radius 560m is designed for traffic moving at a speed of 73.0km/hr (1216m/s). What is the correct banking angle of the road? Homework Equations a=v^2/r F=ma The Attempt at a Solution Forces in t direction: Fnet=Fncos\vartheta-Fg=0...

Could I get a hundred feet of 3" corrugated drain pipe for the air and run it through a 6" corrugated drain pipe for running cooled evaporated water which would be pumped out of one end and gravity fed through the other end. As for the air "tube", I would run one end into the home at one...

Homework Statement recently, i was on an assignment to develop a system or product based on 8085 to help handicap people.the assignment include software and hardware interfacing.any idea or suggestion please?i wonder what product can be create to help handicap people.need some direction to...

Hello everyone, I'm a first year student currently majoring in math/secondary education. I've been researching different schools around my area because I have become really interested and set on switching to majoring in physics. Problem is, I want to have ,for myself, a more specific idea of...

hey, I'm 15 years old, and I'm still going to high school:) But Physics has been my main subject of study for a few years now(since i was 7 to be precise) and i understand many complex things that are above my age category such as Newton's laws and vectors, projectile motions, electronic...

I have an idea that I would like to read up on but, I'm not sure what the best path would be. First, I need to determine if there is a reasonably priced and safe material that can have its color changed when exposed to a low-level magnetic field. I would prefer a material where the color...

"Consider a first order linear PDE. (e.g. y ux + x uy = 0) If u(x,y) is constant along the curves y2 - x2 = c, then this implies that the general solution to the PDE is u(x,y) = f(y2 - x2) where f is an arbitrary differentiable funciton of one variable. We call the curves along which u(x,y) is...

One idea that just came to me relates to the "pendulum fallacy", whereby people mistakenly think that a rocket is hanging by the nose from an imaginary string, instead of actually resting on top of its tail/thruster. So then, what if you could position a lot more of the rocket/lander's mass...

Please give some idea! Hihi everybody... have any new suggestion for doing final year project??

There are many people out there who assert that physics and science is just a man made invention, made by convention. They say a bunch of people just decided and agreed to say that the laws of physics are what they are and that since it was all just made up arbitrarily, this means it may not be...

Yeah, it's stuff like this that makes me contemplate my existence as a physics PhD student. http://www.straitstimes.com/Breaking%2BNews/Singapore/Story/STIStory_418626.html This reminds me of another PhD dude I heard about last year who drives cars for a living...

I recently had an idea which is revolutionary to car travel. I would like to actually produce a prototype and gain publicity/funding for the idea, but I don't want to do anything until I have ownership of the idea. There seem to be several options available, but since this is my first attempt I...

Hi fellow thinkers. I need constuctive criticism on the following:- Imagine a tube circling around into a closed loop - like a hoop. Inside the hoop is a ring of connected bar magnets all facing the same way. Pressurized steam is fed into the hoop - and exited in such a way as to spin the...

I am thinking about doing Honors Physics. Is getting the major in math as well a good idea?

I don't get it...even Guth from MIT who is one of the pioneers of the big bang concept says that "we know that something banged, but why it banged and what caused it to bang is another story" - quoted by memory but the meaning was like that. So...some people think they are too smart to realize...

I'm soon starting my 3rd year of my degree. Were allowed to select our modules now, and basically decide what we want to go into, i.e. fluids/thermo, materials, stress analysis etc. Were also given the opportunity to choose one module that is not engineering related. I was thinking about doing a...

Has Anyone Ever "Stolen" Your Idea? It seems fairly common that people at least claim to have had an idea that someone else capitalized on before they could. How many PFers have independantly come up with ideas only to find that someone else beat them to it or maybe even came up with it...

A certin chemical reaction is carried out at 45C and the rate observed is 280M/s. What will the rate of the reaction be at 55C? i have no idea what equation to use for this problem could someone break it down for me step by step

So for a project what I want to do is experiment with dropping a magnet or a piece of metal down a tube and seeing the effect on its falling speed. My first idea is to wrap copper wire around a piece of PVC pipe. I would then hook it up to a battery to make it into an electromagnet. If the field...