Physics

hi, i was wondering what you know about plasma just to see if it could help me

I have one question here,I fail to understood what is Q of the system,is anybody has an ideal on this? An object of mass 2 kg hangs from spring of negligible mass. The spring is extended by 2.5 cm when the object is attached. The top end of the spring is oscillated up and down in SHM with amplitude of 1 mm. The Q of the system is 15. What is angular frequency for this system?

Can anybody give me the hint where to start on this question? Two simple harmonic oscillators of the same frequency and in the same direction having amplitudes 5 mm and 3 mm, respectively and the phase of the second component relative to the first is 30°, are superimposed. Find the amplitude of the resultant oscillation and its phase relative to the first component.

We have a box filled with gas, and a piston that can move horiziontally. There's no external pressure (such as air pressure, etc). Now, If we compress the gas by applying an external force to the piston, we do work on gas, right? Therefore [math]\Delta W[/math] should increase (I'm assuming that [math]\Delta U = \Delta Q + \Delta W[/math]). This makes sense to me. I note that the volume decreases in this process. This force seems to have done work against the random collisions of the piston. In an adiabatic expansion, it's said that the gas does work. Against what? Plus, it's said that Q is decreased. Since this's an isolated system, this means W has increased. The gas d…

I have very basic question, one function of domestic air condition is to cool air can any body tell me other functions more than that?

Does light undestroyable? and it will just keep reflecting to different place? Or will it be absorbed by something? Or will light just dim out on its own?

Hello folks Im not a scientist, nor do i claim to know much about science, at all. But, this seems to be the place to find this out! IF I were to be suspended in a Large perfectly round and smooth Sphere, and this Sphere is completely mirrored inside, with an ambient light source (for example hanging through the top above ones head).. The question is, What would I see?

I just had one of those brain waves, most of them are nonsense but best to ask anyway. What is the limitations of using a charged array of cells which when hit by certain wave length or strength of light would release their payload into a ccd type detector to produce the end result of being able to store the rough distance away from a camera. I imagine that when the flash is initiated it would also charge the array, I've been thinking abut the fact that the times involved as so small that it would be very difficult with objects so close to the camera (stars and Galaxy's I gather are simple) which is why I wanted to think about ways of doing it with physics instead…

Is there a maximum distance that gravity could be detected? Assuming any instruments could be used? (invented or not) And would there be a minimum force that gravity could cause? or is there no minimum Any help would be great.

How is centripetal force applied in gymnastics/acrobatics?

Can anybody please tell me about good physics chat available out there? Also how to use SFN chat.I clicked on the provided link but what I get is a blank page with no activity.

I was wondering if this experiment is physically possible... Fill a small oblong container, like a plastic tube, with water. Now place the filled tube in a high-voltage electric field, possibly created by a Van der Graaf generator, so that each end of the tube points at each electrode. Since water is a highly polar liquid, this will cause all water-molecules to point in the same direction, trying to cancel out the electric field. Now freeze the water and turn off the electric field. What do we have? A rod carrying an eletric field without spending energy, just as an iron rod may carry a magnetic field? best regards, Michael

There's been a lot of articles published recently about a new Seth Lloyd paper regarding the preservation of information which enters into or evaporates out of a black hole using the final-state projection hypothesis: http://www.physorg.com/news11202.html http://physicsweb.org/articles/news/10/3/1 http://www.newscientistspace.com/article/dn8836-black-holes-the-ultimate-quantum-computers.html But this is the only paper I was able to find, and it's dated 2004: http://arxiv.org/abs/quant-ph/0406205

I was cooking a roast on one of those glass pans with the sides only a couple inches tall. Had it in the oven for 45 minutes at 350 degrees. I take it out and let it sit there while I ran back to the TV to see what was happening. All of sudden "KUUURSCH!". I come back, and there is glass and juice all over the kitchen. The roast had glass stuck to it like someone was shooting a glass gun at it. It took me 3 hours to clean up. What is the science behind this?

Hi everybody. I was just wondering do all photons and neutrinos really have zero mass or is this just to make equations work? It just confused me because my physics teacher told me that photons have zero mass, and this allows them to travel at the speed of light without becoming infinitely heavy; yet i know that photons do have a momentum, so it would seem that them having zero mass would be impossible. Can anyone help me resolve this? Thanks in advance. P.S. if anyone has a good knowledge of quantum physics, please could you have a look at the Quantum evolution thread I've posted in the physics forum. I'd just like to know what you think.

I have a question about black holes. I dont know much about them but I was thinking about it the other day and couldnt figure something out. From what I understand, black holes are stars that have collapsed on themselves and now have gravity so powerful that light cannot even escape it. My question is this. When the star collapses all it does is become more dense (or so i would assume from the word "collapse"). So that means the original star had the same amount of mass as the black hole. So then why wouldnt the original star have the same amount of gravity that the black hole has? Why wouldnt regular stars trap light?

I am a final year Product design student and i need help with my major. I am doing a medical device that uses quantum cascade laser technology to take readings of the patient. I am trying to find someone who might tell me what a quantum cascade laser consists of and what components are required to power such a laser? Also, metaphorically speaking could this technology be reduced to the size of a device such as a mobile phone? Sorry i haven't given to much away but spies are every where! If anyone could assist me and get back to me, then i would be extremely grateful Paul

For example, if you put a book on the table, then would it be harder and harder to lift the book when you are increasing the weight under the table, on the floor? Since more mass means more gravity between two objects

Hello, I have some polymorph and i think its really good. However is there anything like polymorph that becomes flexible at 60 degrees Centigrade but when it sets its more soft like a soft rubber ? Is there such thing ! and can you tell me were i can get it from Thanks a lot

what damage does a high dose of radiation cause to body cells?

Today Lisa Randall gives a talk at perimeter institute as part of the PI public lecture series the PI streaming media site usually posts video of these talks on the web http://streamer.perimeterinstitute.ca:81/mediasite/viewer/ Whether or not you're a fan of Randall, or of brane models, you might enjoy checking this site out. they have videos of lectures by a number of prominent people----e.g. Roger Penrose, James Hartle, Lee Smolin, Renate Loll there is a sidebar menu on the left----for some of the following you have to scroll down on the menu Randall's talk will probably be in "public lectures" Loll's talk is in "emergence of spacetime worksh…

Can anybody explain to me why holes are found at the top of the valence band, whereas electrons are found at the bottom of the conduction band.

Can anybody give me the physical meaning of the pointing vector S=EXE for time varying fields. What are its units?

I have one question here which I need clarification. Automobile has two headlights. What sort of interference pattern do you expect to see from them?

Anyone can help me on this one. A plane wave of wavelength [math]\lambda[/math]= 550 nm is incident normally on an opaque screen with three narrow parallel slits separated by distance [math]a[/math]= 2.3 mm. An interference pattern is observed on the other side of the screen at a large distance from it. (a)At what angles are the first principal maxima adjacent to the central maximum? (b)How does intensity, Imax, at the principal maxima compare to that from a single slit, I1? in (a) can I use asin[math]\theta[/math]=m[math]\lambda[/math] to get the angle?