Physics

Hello! Gotta question here about Circular Motion... we all know that a = (v ^ 2) / r f = 1 / T and F = ma... Then how do I know which formula to use? For example, Calculate the force of gravity on a spacecraft 12,800km (2 earth radii) above the Earth's Surface if the mass is 1400kg?

I know an AC current can be rectified to a DC current with a diode bridge, but does the magnitude of the voltage and/or current change? If so, how. For example, if one had an AC current at 2 A and 12 V, and one converted it to DC, what would the current and voltage of the new DC current be? Btw, let's assume that the process is 100% efficient.

Hey guys! I think this topic belongs here anyway..but please bare with me if it doesn't As you can see, this topic is about the big bang theory. At school I'm currently doing coursework in Physics. At the moment our latest piece of coursework is to find out about the big bang theory, write down the big bang theory and back it up with scientific evidence. At the moment I;m very stuck with it all. about writing down the big bang theory. I don't know exactly what to write down? And scientific evideence. I don't know where I am supposed to find scientific evidence on the net. Is anybody willing to help?

Depending on how you define friction something could arguably never be frictionless. However one could create a gear that removed contact friction other than between a solid and air magnetically. Take a diamagnetic block of material with a cylindrical fixed magnet some distance above it, between these two items are a 2nd this time optional fixed diamagnetic block and a cylindrical floating magnet. The floating magnet is delicate, you could probably bend down to inspect it and breath on it too heavily knocking it off onto the magnet above or out of the edge of the experiment. However if careful one could get the floating magnet to levitate and spin slowly loosing speed…

Hi Id like to know how to work out what the maximum amount of gas i can get down a pipe is. The gas is methane. Its composition is roughly ch4 @ 59.5%, co2 @40%, 02 @ trace, h2o @0.5%, Nox & Sox = Trace, HCL = Trace. It is biogas and the temperature is around 34 C entering the pipework and 6 C before use. The Pipework is various diameters but it has a bottleneck minimum of 6" The pressure at the start of the system is around 15mBar / 150mm water gauge. The pressure varies across the system with diameter. Thanks for your help

Is it possible to trap light forever via mirrors? see example: So if I was to turn off the laser gun would the laser beam inside remain?

BTW, D H, I know I'm a puny undergrad, but this is really interesting; we just learned in class something about distribution of mass (and charge, they seem to have the same general concept). The professor didn't get into it too much but he did say that dipole moment (quadruple moment, etc) define the general shape and 'distortion' of the mass. Is that what you are talking about (simply, of course, I'm sure its a lot more complicated than that) ? btw.. hairy mathematics or hairy mathematicians? .. both can.. be.. uh.. challenging.

Hello. This is my first post ever here, and I'm pretty sure it's not in the correct section, and I apologize for that. So the atoms in a molecule vibrate in relation to each other. And when IR radiation is absorbed by a molecule these vibrations increase. Apparently absorption only happens if there is a change in dipole moment. How do the streching and bending effects change dipole moment? Is it that streching adjusts the distance between the atoms or what?

a simple question and hardly merits a whole thread but does anyone know if Heat Rises in a vacuum? I know it doesn`t in zero g, but I`m thinking about a Light bulb or thermionic valve type vacuum, does it matter if a bulb/tube is right way up or upside down as far as glass and base heating is concerned?

is it possible to describe magnetic fields as a form of energy and that certain materials like bismuth are able to repel the energy. let me explain i have seen an experiment were a magnet was floating between 2 bismuth slugs that were separated by a conductor so that there was enough space to place a magnet between then. the magnet then floated, i would describe this as the energy produced by the magnet is repelled by the bismuth, both the north polarity and south polarity energy fields. other materials that are magnetic can absorb 1 of the polar energies.

i was just revising my homework and I was wondering what will happen if you heat gas so much to a point it is supposed to vaporize. does it vaporize? i mean like when you heat a solid it turns into a liquid and when you heat liquid it turns into a gas. what happens when you heat the gas even more! shot thanks>

I know that on top of a mountain, water boils at a lower temperature because the pressure there is lower. Pressure is lower since there are less air molecules there. Can someone tell me why are there less air molecules up there?

why dont magnets affect an electric stream

i reciently heard that nasa was testing different types of magnetic shielding on spacecraft. i was wondering how would magnetics be used as a shielding mechanism, and how plausible even is the idea. if someone could direct me to a site where i could learn more, that would be very kind.

i have prob understandin the following proof......... IN THE CASE OF SIMPLE MICROSCOPE IF IMAGE FORMS IN INFINITY THEN HOW CAN WE PROOVE= MAGNIFICATION(m) = D/f where 'D' IS LEASE DISTANCE OF DISTINCT VISION AND F = FOCAL LENGTH

Hi, I recently started physics and I am so lost! I need to calculate the exact act of a cannon firing a projectile at series of targets a known distance away. Here's what I know: muzzle velocity of cannon: 31 meters/second cannon length: 1.143 meters The targets are, 50 m, 75 m, and 100 m, away. What equation(s) do I use to calculate the launch angles? Any help is greatly appreciated! =D

When I connect two 1.5 V batteries in series, I get a potential difference of 3 V across the terminals. |+|---- |1| | |-| | | 3 V |+| | |2| | |-|---- (Showing battery 1 and 2 in series). Can anyone explain why the voltage is doubled when voltage sources are connected in series? Why, for instance, is current not flowing from + of battery 2 to - of battery 1 (conventional current flow)?

What is sidereal time, how does it differ from solar time?

You know, I got a theory about lazer beams that we could make them by condensing protons into bullets. If we get to a quark, and condense a couple million of them into a bullet? I didn't really think about quarks being in protons- and that they're little molecular charges.

When answering questions of how can space never end, a typical answer-in-question-form is "what is above the North Pole?" or "if the universe were a room, what is beyond the walls?" and then in self answer "-nothing". I see a flaw in those analogies. Obviously, above the North Pole is atmosphere, space, planets, dust, stars. And beyond the room's walls are other rooms with more walls or the great outdoors. Doesn't it seem like when a caveman might say nothing exists beyond the horizon? No offense to anyone, just what it comes across as. Anyone else feel that way?

Could mirror matter comprise a significant quantity of the missing mass in the universe and how would we go about detecting it?

I am currently working on a high school science project and am really interested in doing it on holography. One of my ideas is to do "non-destructive" testing on various construction materials using holographic interferometry to analyze their durability. My basic procedure involves making a hologram of a sample of the material being tested (ex a block of wood), then making a second hologram of the same sample of material with a stress being applied to it (a weight placed on top of it). My hope is that I will be able to examine the holographic film the images were made on, note a difference in the interference patterns of the two images, and make conclusions by compari…

I am was wondering with all the talk and with all the rumors 'I wanted to know the facts' of what would be the first signs a Pole Shift has began 'You know like what to expect and look for'

During a recent trip to Austria I noticed attached to the wires on some of the electricity pylons in the fields what looked like steel or plastic balls/spheres (perhaps 12" diameter, hard to tell from the ground) spaced at intervals along the wire. These balls/spheres were not on every wire just one length. I was wondering if anyone knows what these are used for. They don't seem to have any of these objects attached to the wires on pylons here in the UK.

Plasma balls are cool. They seem to come in two main types though. http://video.google.co.uk/videoplay?docid=4877514184455579319&ei=1IHySL6rK42siALr3OziDg&q=plasma+balls&hl=en http://www.clipser.com/watch_video/594460 And you can get the plasma onto the outside of the ball with a metal item or foil. But look, something new. http://uk.youtube.com/watch?v=9NQcKQ-NNWw So lets build a larger spherical one. EDIT: It's just occurred to me that he is not using his finger to touch the outside of the glass.