Physics

hi, Was wondering, in the midst of M-theory, why there is predicted sparticles. Being like partners for the other normal particles and why they are or need to be heavier than their partners. Is it like a case of (required) equilibrium ?

Hello. Im new here. I would like to know some practical equation to calculate hydordynamic force on elastic and slender cylinder. I have a 2 meter long elastic cable with submerged in a water tank. Water in the tank is rotated at velocity v. A xy table is attached at the top end of the cable so I would like to know the hydrodynamic force on the calble in order to select motor required torque.

According to uncertainty principle, it's not possible to measure the position and momentum of an atomic particle ( say electron) simultaneously. Now, suppose a scientist grows so small in size that an electron is the size of a big ball (or planet) for him. Is uncertainity principle applicable for the scientist also. Does it mean that it's only the size difference that we construe as quantum phenomenon. Just being curious!

I was not real sure which forum to post this one under, so I'll put it here tosee if someone has the answer to it, and if any of you moderators feel compelled to move it, I'll understand your decission. I read, and sometimes do posts on survival and preparedness boards all over the web. Many folks are concerned with these subjects since 09/11/01, and the Katrina hurricane, as well as a host of other possible disasters and events. One thing that I have noticed on a number of these boards is the concern over terrorists getting hold of a couple nukes, mounting them on a couple of rocket launchers aboard a few cargo ships, and launcing them high into the atmosphere ab…

At the moment, the Physics forum isn't very well-organized. For example, where do I go to post a question about electromagnetism? It doesn't belong in "classical physics," because that forum says it's about "facets of mechanics," but electromagnetism isn't exactly "modern and theoretical physics" either. Is there a better organizational strategy that would improve the Physics section?

Hi, hopefully this isn't too dumb a question. However if the first law of thermodynamics states that energy cannot be created or destroyed, would this not imply that whatever existed immediately prior (given that there is no time period we can refer to as 'prior') to the big bang (and therefore before the planck epoch) must also have been another form, or state of energy? If this is the case, then couldn't it be used to imply that something did indeed exist during this period and that consequently the universe can't be said to have emerged from nothing? Or alternatively, is it believed that the laws of physics only came into being after the big bang? Is there no c…

if so, please explains.

In this collision Before= p=100 kg m/s---> <-----p=120 kg m/s After= <--combined unit P= 20 kg m/s In this question when I work out the change in momentum for 2 objects it is not the same. When there is a combined unit travelling after the collision can't you find the change in momentum?

Hello guys, This is from an article I recently read. I have not done any aerodynamics but I'll be so greatful if anyone can explain what this guy means. What I'm thinking is if turbulent air delays the separation of air and the smooth air separates wouldn't the ball swing to the smooth side first and then to the turbulent side when that separates. Also why does turbulent air have lower pressure, in a tube if a fluid is turbulent wouldn't it exert higher pressure on the walls. Thanks guys

Hey I wanted to ask about Solar Sailing and I find this strange and I am quite puzzled as how can mere sunlight power an aircraft. I have looked thru articles on Solar sailing available to me at the moment but I dun get how can sunlight power a spacecraft. is it like solar cells or using light energy

Does anybody know what is the rms value of a sine wave and average value of half cycle of Sine Wave.

What is the mainstream's scientific basis for believing that? Ok, the Mayan Calendar predicts that the world will end. What is the Mayan's logical basis for making that prediction? Does the Mayan Calendar actually give a CAUSE of the apocalypse? Or, does it just awkwardly stop in much the same way as our ability to tell history awkwardly stops at the Big Bang? I've watched so many documentaries on this conspiracy theory, and I have not seen one of them, not one, that I couldn't poke a HUGE hole the logic of. Specifically, why does everyone thing the world will end in 2012?

if I get a paper and blow on top of that. The air would move faster and it would lift but why is it that only air in the bottom pushes the paper, what about the air above the region I'm blowing can't that push down on the paper. Thanks PS: While we are at it why exactly does air move faster in long distance, like aeroplane wing?

At 0K(though impossible to achieve), bodies are at their lowest energy states as they've expelled their energy to the surroundings. This should mean electrons lose their energy too and fall into the nucleus. Or, atoms can collide with each other as the density is infinite. This can create a big bang. Thus, big bang at 0K? Is this one reason that 0K can't be achieved?

hello people This is an extract from my book about my problem http://img693.imageshack.us/img693/3506/thrustforce.jpg I have an explanation for this but not sure about it : Pushing the rocket with a high speed when a great amount of burnt gases are pushed backwards with a great momentum , the rocket gains the impulse forward with an equal momentum (According to the law of conservation of linear momentum). Also thrust exerts a force upon the rocket , the rocket answers in the opposite direction with a force equal in magnitude (According to Newton's third law). F net = d(mV)/dt and since both mass and velocity a…

Hello guys, This might seem a basic question but my physics is not that good. So in a normal pipette when you squeeze the top bit, do you create an area of high pressure there, and then when you put in a flask with liquid and release it the air escapes, and then the atmospheric air pushes on the liquid and fluid comes into the pipette. Is that what happens? Thanks

I have a point charge in a conducting sphere. The charge can be placed anywhere in the sphere & is acted on by the image charge effect & gravity. If the charge touches the side of the sphere within time t it is considered deposited. The image charge is given by: F(x) = -q divΦ(x) Φ = - q 1 4πε0r0 1-R2 r0 is the radius of the sphere. r is the radius at which the charge is at. And R= r/ r0 I’m trying to find the volume of the sphere within which the charge will definitely deposit in time t. I have modelled this situation using excel. Due to symmetry I’m only modelling a quarter of the sphe…

Hello all, I 'm looking for a website/reference that would give the real and imaginary dieletric constants of various materials ( gases, water, solvents, oil, plastics, minerals, metals etc.) on a wide range of EM wavelengths. I would like to get an overview of who absorbs in what domain. Thanks for your help, McCrunchy

Quarks were formed during inflation in the big bang. The smallest amount of time we can extrapolate back towards the big bang to is 10^-43 seconds, where it is thought the temperature was 10^32 and a density that is not describable. So during this time, it is thought there is only one force; a combination of four forces. So the question is, where did the forces come from? Where did matter and temperature come from? Is this unknown unless you invoke M theory or the uncertainty principle? Also can someone explain the uncertainty principle. Does nothing mean absolute nothing? Or does nothing mean not matter but forces and vacuum?

Is it correct to say that one does not see an object but the light which bounces (or that it emits) of it?

I just read another of those posts where someone said he's a layman with interest in ... and Theoretical Physics. I have a vague idea why people are interested in that and for the most part I'd advice them to rethink their interest - but that's not what I am going to ask about. Another instance I met the term and was a little puzzled was on Wikipedia where I wrote that the Einstein notation is mostly used in relativistic physics and someone "corrected" me and wrote "theoretical physics", instead. My question is What does "Theoretical Physics" mean to you? As a matter of fact, I don't really know what it is to me. Generally, I tend to think of i…

What is enery? I understand that there are different types of energy and that it is either absorbed or released during chemical reactions but what exactly is energy? Is it some kind of particle, wave, heat?

Will a black hole be infinitely small while it's absorbing more and more materials, since every particle includes an infinitely small universe internally?

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I would like to present my idea of a 100% combustion engine pollution collector to replace the catalistic converter. This with my idea of lifting petrol below could guarantee 1000's of yeas of motoring. Also work well on factory chimley etc, eliminating air pollution. What do you think? Might not need the gel belt and scraper, just the u-bend effect? Can also remove the gelbelt and scraper and blow the exhaust fumes through oil within layers of mesh to produce small bubbles. Take a 50cc moped engine, add some fishing wire and a bucket. Drop it down an oil well and winch it up(1.5 miles). At only 30 mph it will take only 2 minutes to reach the surface…