Physics

One of the main reasons Physics debuck UFO's is no propulsion exist today that can do the things UFO can do.A UFO that can hover, fly over a city for hours , fly very slow than go at speeds nothing humans have invented that come close to that speed.A UFO that makes no noise or very quiet!! A UFO that cause all electronics to shutt off and cause cars to stop running and planes to shut off. And reports of some UFO crashes where by Physics debuck that advanced Alien race that can go from one star system to other and is millions of years advanced technology would not crash. No propulsion system can do any thing the UFO can do chemical propulsion,ion propulsion ,plasma…

Ok, so with electricity we have a charged particle creating an electric field, wherein a test charge further from a field-generating particle has a higher potential energy than a test charge closer to it, and so far this is analogous to gravity, in which case we have an object creating a gravitational field, and a test mass further from it has a higher potential energy than a test mass closer to it. In electricity, the test charge's ratio of potential energy to charge is known as electric potential. In gravity, I assume that analogous to this would be the ratio of gravitational potential energy to mass for a test mass, which would be the product of the gravitational c…

Let's say someone were holding an object (like a pencil) at a position away from the centre of mass, such that it would rotate from the gravitational torque if held still. Would there be a way to spin it (as in, about an external axis, while the line from the centre of mass to the pivot is in the same direction as the radius) such that the torque from the centripetal acceleration would just cancel out the gravitational torque?

Ok, so first off, angular momentum doesn't need to involve rotational motion, and a particle can have "angular momentum" with respect to an axis if it is moving in a straight line that doesn't pass through the axis, right? Also, if the particle had a constant speed and constant mass, then moving along the axis, its angle with respect to the axis would be perpendicular when the distance TO the radius is the lowest... does this imply that the angular momentum of such a particle would be constant? Also, as for the angular momentum of something thrown into the air... let's say we had a water bottle that was filled part way. It was thrown into the air such that its plane o…

Hi everyone, I have a question relating to gafferuk's but probably a more fundamental one. Don't get me wrong. My math skills are completely lacking in this area and I still haven't reached the chapter of trigonometry and vectors in my college algebra textbook. So please if you could provide an answer which is not mathematically rigorous as possible that would be appreciated. According to Newton's first law, it takes a force to make a massive object to start moving from a rest position. If an object starts moving by a force from a rest position, it will keep moving unless stopped or slowed down by some kind of force such as friction or gravity for example. …

Hi, I have two very specific questions. I was trying to read this paper : http://downloads.bbc..._connection.pdf and i noticed that equation 3 and equation A6 were different : Eq3 : L(t)=Q(t)/£(t) (not dimensionally correct) and Eq A6 : L(t)=Q(t)/£(t) * delta_t When you read under equation 3, you understand why this is like that ; they say : "As seen in Eq.(A6) of Appendix A, lifetime indeed has the dimension of time, being multiplied by the sampling time interval (which is here equal to unity–1 day)." Questions : 1/ Is it ok to have a dimensionally wrong equation if you say why in the text right next to it (i.e. number…

i thought that if the individual electrons in a current had its own magnetic moment, shouldn't negatively charged particles be also possess that property ?

can anyone pls explain me the working of an inverter....the battries in the inverter gives very high voltage but from inverter me get very less voltage supplies...how is it so???

if light is passed through a prism on earth it reveals all the wavelengths/frequency of light that we see as colors. but what would an anti matter prism produce would the colors be inverted or what. just a question thats been bothering me anyone have answers

Could the Earth be flat, but bent by time? In a quad-helix time-like cube spinning 1/4, creating a full circle? Just a thought.

Hello, I'm currently conducting investigation on how the surface area (or width) of a blade on a 3-bladed fan effect the power of the wind produced. I have done lots of research and it seems that there has been lots of experiments and calculations done on the effects of the number of blades and the effects of radius/diameter on power. However, there is little information on the effects of the surface area. I was wondering whether someone can help me explain the relationship between the surface area of the blades and the power, whilst keeping the radius and number of blades fixed? I have collected some data through an experiment where I had fans of the same …

Would someone lose weight just by thinking? Synaptic connection need some energy right? And more energy to consume means more calories to burn. So how many hours a day should i spend on thinking to lose a pound in one week?

Hello everyone, Ok so I read that the reason they are in free fall is because they are going in a circle like this , and the earth curves away from them at the same time or something, could anyone explain it to me simply. Also why don't astraunauts get pushed to the periphery of the space ship by the centrifugal force?They are not wearing belts right, do they I don't know? Thanks

i was lying down and start to thinking randomly. I was thinking about the scale of thermometer. It's just weird to have something below 0 degree. I think 0 degree means that there's no more heat to release. So how come some object can become colder when there's no more heat to release? Is there any limit where something can no more become colder? If there's any then we should make a new scale of degree. I'm curious about how it's gonna be if we just keep absorbing heat from one object . Will we found a new state of matter? I've read about plasma though. I'm new in science world and my major doesn't even close to science. So forgive me if the question is not…

So supposedly angular momentum of a system is conserved, right? Well, consider this video: If, hypothetically, the cat jumped while the roomba was rotating, would the cat be spinning at an angular velocity equal to whatever the angular velocity of the rotating roomba was when the cat jumped?

In free electron laser(FEL) is used magnetic field to make electron move on sinus-like curve - thanks of synchrotron radiation and bosonic nature of photons is created coherent 'light' beam. http://en.wikipedia.org/wiki/Free_electron_laser All fundamental equations of physics we use, conserve CPT symmetry, so imagine above picture from the point of view of such symmetry - we get position moving on this sinus-like curve in reverse direction, producing light beam ... photons traveling back in time! To understand it, imagine 'standard' free positon laser - it produces photons which goes forward in time and space and finally hit into something, for example excitating it…

Let's say two objects of unequal masses were accelerated to the same velocity on separate flat, horizontal surfaces with the same coefficient of kinetic friction. Assume neither object was lifted off the ground and that neither went through a surface or over its edge. Which object would be the first to come to a stop? My tentative guess for this is that they'd come to a stop at the same time. Here's why I guess that. The forces on each object include forces of gravity, friction, and the normal force; force of gravity would be directly proportional to mass, normal force would be identical to force of gravity (given the lack of vertical motion) and friction would be…

“Action at a distance” whenever this comes to play, in physics we tend to think of this in terms of fields whether it may be due to Electric, Magnetic and Gravitational (Well I know these only). Oh yes there’s one more and its Einstein’s Fields equation well I don’t know much about it. So whats the real concepts behind field. Because from my intuition In order to make any change, movement or disturb something you need to touch it, for example if I want to move some object then I need to touch it and give it some force and that seems to be really in sense. But on the other hand there are few physical phenomenon like Electric, Magnetic and Gravitational forces in which th…

I notice that if I hold something in front of but somewhere between my eyes, even something in the middle will be further displaced from the center of my field of vision (assuming that's what it's caused) from closing one eye than from closing the other. Why is that?

Hi everyone, I have an optics question that I hope someone could help a poor chemist out with. I have a Xenon lamp that directs most of the white light in a liquid light guide that then comes out and is collimated at 1" with a lens of the same size. If I wanted to collimate the beam at say 1/4", what is the best way of selecting the appropriate lens to use? There seem to be a bunch of lens equations and I'm not sure which to use for a collimating application. For what its worth my point source is like 0.125" and I think my beam divergence is something like 25.5 degrees. (0.125" goes to 4" beam when viewed 4" away.) Thanks so much for your help!

If we're to simplify damped and resonant oscillations by assuming that there is some specific pattern with which the oscillation's amplitude either decreases (damped) or increases (resonant) then is it still sinusoidal or does it qualify as something else?

Light exist without any matter, charge or anything else for that matter.It consists of 2 fields ( a magnetic and an electric) which oscillate.Both of them sustain each other. The thing which amazes me is that the the existence of the fields is independent of any causing 'thing' along with it.The wave representation of light can clearly be explained as a solution of maxwell's equations in a vacuum .I was wondering are e.m. waves the only solution to these equations.If not what are the others and how would one go about creating other such stable configurations of fields. (please note I intended for this thread to be a general discussion and do not mind even if it drifts s…

So I had a hypothetical idea a while back involving a large rotating wire-mesh (of course, in hindsight, it would be more likely to attract lightning if there were pointy ends distrubuted throughout said wire mesh) turning high in the sky, to attract lightning during thunderstorms, and run it through whatever it leads to. (ie. epsom-salt water for electrolysis, lightning electromagnet, etc...) One idea I had for what it would lead through is a flat sheet of tungsten, immersed in water. As the lightning runs through it, the tungsten heats up; 60 watts of electrical power is enough to light a tungsten bulb significantly; imagine if I were to run hundreds of thousands of…

Is there any difference in the term 'White' and 'Colourless' in Optics? Is a light ray colourless or white. In many books colourless and white means one and the same. But white is the colour of milk while water is colourless.

Let's assume I hypothetically managed to get my hands on a large quantity of magnesium ribbon, and I decided I'd use it to start a bright fire. I'd use something underneath it to ensure the fire was strong, (such as gasoline) but the key component of the show would be the magnesium itself. First off, I assume it'd be dangerous to have the flame viewable directly, so the flame itself would only be recorded by camera. But let's say I had everyone involved facing away from the flame, and instead looking at the buildings, the ground in front of them, and maybe the clouds depending on the conditions. Which brings me to my next question... how would the weather conditions (…