Classical Physics

These are some thoughts about Time. The usual way of describing the space-time continuum is the following: we have 3 dimensions related to space, and one related to time. The 3 spatial dimensions are given by spatial coordinates (x,y,z) & the temporal one is added to form a four coordinates system (x,y,z,t). So far, so good. But we know from our observations that time can be used as a representation of distance. It is a consequence of the observed Speed Of Light. We can replace a distance-unit of 300.000 km with a time-unit of 1 sec. It doesn't change a thing. So that we can build another spatial coordinate system (3D spatial) made of 2 orthogonal angles and …

Hello, I'm looking for a way to determine wether one object is in a closed elliptic orbit around another based on mass and state vectors alone. For instance, if an asteroid is passing close by Jupiter, how do you determine wether it has actually been caught up into a closed orbit (assuming mass and state vectors are known)? At all times it is orbiting the sun, but how do you determine wether it is also orbiting Juiter? Cheers, Mike

Im not a since guy but I been thinking about this question for a time now so got an acount here and hopfylle we can sort it out. (Im not a native english speaker so sorry for spelling errors) Is it possible to get an object floating perfecty still at a XYZ coordinate that i put in at the ground without using motors etc. For example can i get a small baloon floating at a hight of say 500meters, 1000meters and so on only using some special gas or special temperature of the air in the baloon. I guess the hardest part would be it staying still in XZ coordinates? Looking forward to any information.

I understand that only odd harmonics (1st, 3rd, 5th, 7th etc.) can be formed from a closed-open pipe such as a clarinet. So (from my physics book) why in this graph of harmonics of the waveform of a frequency produced by a clarinet does it show odd & even harmonics?

A couple days ago, I had a basketball and about 200 grams of applesauce in a plastic container with a lid. I put the applesauce on top of the basketball and just dropped it onto a hard wood floor from about 5'. When the basketball hit the ground, the applesauce can shot strait up, dented the ceiling and the can of apple sauce exploded. I was wondering where the applesauce got all that energy from?

our teacher was explaining the equivalence of kelvin plank & clausius statement of 2nd law. i would like to know if there is any proof of them individually. thaks in advance.

Without friction would water flow or any liquid like blood through veins and arteries? I'm not including the surface that the water is flowing on just the water molecules. Hope that makes sense.

Hello, I'm tampering with a little computer simulation of mass spring damper systems, and somewhere on the net I stumbled across this equation: F = m g j − k D (sin θ i + cos θ j) − b (Vx i + Vy j) F = force m = mass g = gavity k = spring constant D = string length displacement Vx = Velocity X Vy = Velocity Y Maybe someone here can shed a little light on whats going on here and wether this equation is even right? And what does i and j stand for?

calculate the final temperature attained by the 2 equal masses connected by a carnot engine whose initial temperatures were T & 4T(absolute temp.) and specific heat capacities of both masses are C. pls tell me how to approach the sum. answer is 2T.

Someone said on another thread that the order by which events happen (the sequence of events) can depend on the Frame Of Reference. Napoleon Bonaparte (1769 – 1821), a figure of the past. From my Frame Of Reference, can I see Napoleon's second marriage in 1810, exactly 200 years from now? No. Or yes, with the help of my E.T. friend, living upon a planet distanced 100 Light Years from the Earth. He has placed upon the surface of his planet a mirror facing the sky. With my good telescope, I can see in the mirror the Earth as it looked 200 years ago. And there is Napoleon entering the cathedral, I can see him. And that is exactly what my E.T. friend is observing from…

After a boring day of law school classes, I began pondering the ever illusive (and most definitely impossible) perpetual motion machine. Don't ask why, perhaps I was bored. As I am not trained in any form engineering or physics, I have tried brainstorming some possibilities with the only brain I have - one of lackluster quality. In conjuring up one particular idea, I acknowledged that I need a little more information pertaining to automatically retractable cords or wires that recoil upon pressure or certain extension and release. For instance, I have seen a computer mouse with a cord that retracts automatically when it is extended to a certain length. I thought th…

hi there, im new to this website and this is my first thread, dont know what to expect but i have high hopes. so here goes. i am doing some research on how electric guitars work, i have some basic ideas of how the vibration of the string is converted into electricity via the pickup. but im still not sure. here are the things i need help with 1. how do standing waves relate to guitars? 2. how is the frequency of the note affected by the properties of the string? 3. how does the pick-up work? 4. how do we adjust the output volume of the guitar? any help is appreciated, thank you. i hope this is the right section

how would levitation work? such as magnets when they dont like eachother, and is it possible to levitate stuff?

Okay so I've been wondering if there is a way to calculate the force on a magnetic material (that is magnetized and producing a magnetic field of its own) from an electromagnet that produces its own field. This is not a trick question or anything of the sort and I've been trying to find detail on this, but I have failed to find how one B interacts with the material of another producing its own field. This question comes about to me when thinking of an electric motor and the force produced by an electromagnet on a permanent magnet. Does anyone have any insight?

Good afternoon, My name is Joe and I am on a quest to get a complete understanding of gravity and there are a couple questions which I am beginning the quest with. Does a planet or object in space that does not spin create or have gravity? Does the size or the mass affect it's pull on other objects? Is it possible to distort and direct gravitational fields? thank you

Could you please explain the answers to these 2 questions to me or tell me what site to visit that would explain it? thanks! A positron orbiting an antiproton would make up an atom of? A. unobtaninium B. anti-hydrogen C. positronium D. anti-helium Compared to the energy it takes to separate oxygen and hydrogen from water, the amount of energy given off when they recombine is? A. much more B. slightly more C. the same D. slightly less E. much less

Help with science experiment: proving the law of conservation of mass? Ok well for my homework in science class I am supposed to design an experiment that proves the law of conservation with these materials: triple beam balance; NaHCO3; vinegar; Erlenmeyer flask; balloon, water, scooplula, graduated cylinder. The problem is, I don't know how to make an experiment with those materials lol... If anyone could help me out a little bit here and show me how to make an experiment with these materials or even just help me a little it would be greatly appreciated.

hi again i am very interested in energy is it possible to get significant quantities of heat from thin air by compressing and cooling? so u can have the 2 types of heat engines together u can like have a piston to compress air sufficiently to boil a volatile liquid just like an air conditioner then the volatile liquid can have a high temperature in relation to the environment and we can extract more heat for electricity to partially power the appliance and if possible ( which i have doubts about) provide minimal surpluses? thanks

Hey guys, I'm actually not sure which physics subforum this fits into, since I don't remember exactly what those rods were.. I'm hoping someone can help. A while ago a friend of mine from the department told me about a type of metal-like rod that can bend and flex, but retains its original shape when charge is passed through it. I don't remember the name, but it has one. I remember that I *did* find it online, but I can't, for the life of me, find it again. I also have no access to that friend anymore, so I can't ask again, sadly.. Does anyone know anything about this? Any help will be appreciated! ~moo Merged post follows: Consecutive posts merged…

Greetings all, my first post here is a topic of great personal interest originating from a movie. It's something I have struggled to find online and it's either very simple or very complex. Either way I haven't found links about it which tells me I'm looking for the wrong thing, no-one cares or it simply isn't possible. We've probably all seen Gene Hackman and Will Smith in Enemy of the State. 'Brill' used a copper mesh cage to shield himself from external radiation. This made me wonder if this would actually work? Stop cell phones having reception. Prevent harmful radio waves passing through (eg. GSM, Radar, Television, satellite, appliance etc..) We wer…

I'm trying to get across to my students that if a projectile is thrown horizontally and the same kind of object is dropped from the same height and at the same time, both objects will hit the ground at the same time (neglecting air resistance). I had them put a washer on a ruler, and hit another washer off the table with the ruler- so that have one washer drop and the other one be hit at (hopefully) the same time. A few of them weren't convinced. Do you have any ideas for demonstrations or videos to watch to help prove this? Thanks.

Does anyone know whether or not the levitating boulders on Pandora is realistic? I mean I know that at the very least the science behind it is sound; superconducting material levitating in the presence of strong electromagnetic fields is a well known phenomenon called the Meissner effect. So since "Unobtainium" is both a room-temperature superconductor and gives off strong magnetic fields, theoretically it would levitate; but could the Meissner effect really cause whole boulders to levitate like that?

Imagine hearing voices in your head that are not from people in your vicinity and when you are not suffering from schizophrenia. I have been informed by several people that they experience this phenomenon, crucially without showing signs of mental imbalance. I believe their testimony. I wonder if our Defence Ministries have allowed these people to be used as 'non consensual subjects'? If this is true, it would mean that the Governments of Britain and America are surreptitiously allowing the use of these machines against their own public. What is the Endgame though? And the same article in wiki seems to point to the development of devices used in a non-…

Not sure if anyone posted this yet i searched a little on the site but did not find anything. anyway check this out and let me know what you think. Author of paper and work in a PDF file you have to download to see in upper right corner of page http://arxiv.org/abs/1001.0785 Audio: http://www.twis.org/audio/2010/01/12/420/ this is a very good but silly podcast you can get a lot of Breaking news science stuff from. Video form the site: http://staff.science.uva.nl/~erikv/page4/page6/page6.html cited info: http://en.wikipedia.org/wiki/Holographic_principle more: http://www.stumbleupon.com/su/25KFJt/arxiv.org/abs/1001.0785 more: http://www.scient…

Today I filmed my coffee cap experiments (with hot water). Any comments?