Physics

Hi, I have a question. In this physical review letters article, what particles do [math]\bar{v}[/math] and [math]v[/math] stand for?

I was googling trying to find some help with these classes I've been taking and I ran across this website called, Cheat A Lot.com. I wasn't really sure who else to ask so I joined ScienceForums to ask the moderators and other students if they have any experience with this website or any others like it. I'm somewhat split on my morals here... Yes or no? anyone? This is what their webpage says: [removed] is an online service provider of homework auctions. Registered users can serve as Students and/or Tutors. Students post an assignment and wait for bids. Tutors find assignments and post the amount for which they are willing to help complete the as…

What are all of the dimensions? I have an idea what the 5th and 6th dimensions are, but I don't understand the rest. (Maybe some clarification on the 5th and 6th dimensions.) Thanks,

Is it possible to create an animal, which weighs over 200 lbs, that can lift things weighing 850 times its own weight like what a rhinoceros beetle can do? I've heard according to cube-square law the larger an animal are, the smaller the ratio of lifted weight to its body weight is generally. Can this barrier be overcome by some scientific methods?

Is it always correct that the bigger and higher density a planet is and has, the greater gravity of the planet is? And therefore animals on the planet would be shorter and broader rather than taller and lankier?

Imagine we hold a flat surface and there is a spinning top (gyroscopic toy) on it. While changing the angle of the surface, the top generally follows the change, but it additionally makes some complicated 'precessive sinusoid/cycloid like motion' around the expected trajectory. Electron's spin is something different, but it sometimes is imagined as a spinning charge ... it's quantum mechanical phase rotates while time change ... there is Lamor precession ... Let's look at Bohr model of atom - quantum mechanics made it obsolete, but it still gives quite a good predictions http://en.wikipedia.org/wiki/Bohr_model It's main (?) lack is that it says that the lowest ene…

Hello guys, In electrophoresis I mean sorry. In electrophoresis is a similar electromotive force applied to all particles or are all particles accelerated at the same rate? What I mean is let's say if every particle gets 10N. F=ma and bigger particle would travel slower. So can't I include this in the answer. If they are only accelerated at the same rate I can understand how different particles would have different resistances? So is the answer F=ma? Thank you!!

What if you could use gravitational forces to draw all this radiant energy into the small point? If there was some way to create a sufficient gravitational force you would avoid using materials like mirrors (which would absorb some of the energy you are trying to harvest) and get directly to the gathering of this energy.

Newb here... didn't know where else to post this.... I realize there are rigid solids that will hold a vacuum for a very long time, but is there any flexible plastic or fabric that will hold a medium vacuum for a very long time? Another way of asking this... is there a plastic -- or even a coating that can be applied to a plastic-- which will not allow any molecules found in the atmosphere through? An actual zero-permeable material? How long will the bags used in vacuum food storage hold their vacuum?

Sorry, didn't know if this classified in the quantum section. I'd just like some answers to some random questions. Is there anything in the world which will make electrons spin/orbit (although it's not really an orbit, I know) around the nucleus faster? Why do electrons not spiral into the center of an atom? I believe the name of the force is electrostatis but I don't know anything about it. Why do atoms vibrate and not move in a single direction? What does one mean or what happens on a particle level with delocalized electrons? Feel free to answer one or all at a time.

Good morning SFN posters, I have some questions that I am hoping will be plain old simple knowledge for many of you. I spent most of the night trying to find a few answers for my daughter that she not find in her notes, the book and not even online (granted the way you type things can be your hinderance.) She has a big test tomorrow so any help in figuring these out so she can study them properly would be so much appreciated. Okay so there was the project apollo mission for space exploration, and they placed numbers after Apollo for what I thought was each subsequent mission starting with 1. In this particular question the ask the significance of 11 for Apollo 11 …

Here is my understanding of what are the past, the present and the future. _We know that everything we observe is in the past. We know that an object observed far away is also an object as it was long ago. And we know that the closer the object is, the more close to the present. So the past is there all around me;I am the observator. And the closest objects are very close to my present. The very closest thing to me , myself, my own body, is in the present. Only me, as the observator, is in the present. You, the observator next to me, you will be in your own present. And I, not being part of your present, I am lying in your past. As you are lying in my past. I…

Hello everyone, I really don't have any idea of how the x-rays work actually. Someone told me when light goes through that place becomes dark in the x-ray or something. Anyway if anyone can give me an explanation of how an X-ray work that would be awesome. x ray----------man-------board The x-ray prints on the board right. You can't see the depth in a normal x-ray right? Does everything get printed on the same plane or can you see layers. Organs that are front of others etc. Also what do they mean by antero-posterior x-ray or postero-anterior x-ray? If anyone can help that would be great. Thanks a lot!!

Hi all, watched this Horizon episode recently and was really impressed, thought I'd post the links to it for others interested in fusion energy. BBC Horizon: Can we make a star on Earth? Part one Part two Part three Part four Part five Part six I don't know what you lot think but I tend to agree with the presenter, fusion could well be our only hope. Merged post follows: Consecutive posts mergedJust wondering if anyone has any info on how these fusion reactors (JET, KSTAR, etc) are performing?

Planets Orbit Not Because Of Gravity Energy But Because Of Griff Energy... Why does the moon not fly off? Why do astronauts float in space? Objects fall to earth at the same speed?, All of this does not make sense. If astronauts "float" in space, then there is no gravity in space. So whats the moon doing? I thought there is no gravity in space? Very confusing It may be that each planet or moon is held in a gravity ring and between these rings is no gravity. I doubt this is true. Or is there such a thing I would like to call "Griff" in our universe that keeps things draging along such as the moon orbiting the earth while the earth orbits the sun. (G…

According to this Internet source here some physics majors go on to become professional physicists but the majority pursue careers in fields where they can put their knowledge to more practical applications (like electronics, computer science, finance, medicine etc). So my question is: What could be some of the real life applications of particle physics, supersymmetry, supergravity and the other theories of modern particle physics in medicine, electronics, computers, new power sources etc?

Hello everyone, Ok I thought I knew gravity and just realized I absolutely have a very poor understanding about it. Ok let's say a person was moving in a lift 1. The blood would pool around the legs because of gravity, but my question is aren't we overcoming the gravity force to go up, why would it affect us? Ok the explanation is that upward force from the lift is not acting on the body. But if we are moving up how come it doesn't affect us. 2. Ok what about lift moving down, why don't we feel any weight? Ok the explanation is we are moving with gravity, but if the lift is not accelerating at 9.8 ms2 we should feel the gravity right. 3. About basic free f…

A thought came to my mind. If only we could find or bring from earth the resources necessarily to build a particle accelerator in space, we would not need to worry about safety or space concerns which the future accelerators (i mean those far beyond the LHC) will bring up. So is it theoretically possible to build a giant particle accelerator (even larger than the LHC) in space?

what is its structure like how do u work out how much energy it has what happens when it it comes into contact with a electric and magnetic field and a general explanation please about them

What happens to the energy loss if the iron core in a transformer is taken out? I think the energy loss will reduce, is it right?

Ok I studied bernoulli and I can see how fluid would travel faster in narrowed regions but in most examples I see when something is narrowed the flow is reduced. Is this because of resistance? Also when there is resistance speed in the narrowed section is reduced right? I like to know what do they mean by this friction. Simply I'm asking in most occasion when something is narrowed the fluid flows slower due to resistance. It might be faster than non narrowed part but it is slow because of resistance(I mean if there was no resistance it would be faster) Is that right?

in the classic school experiment where students rub a ruler with cloth and bits of tissue paper are attracted to it, why are the bits of tissue attracted to it when they havn't been charged?

It can be found here. Anyone well on their way to become a bad theorist?

What is second cubed s^3 as in the wikipedia article? http://en.wikipedia.org/wiki/Volt

How does elastic recoil of arteries stop blood pressure going to zero and artey collapsing? Thanks