Physics

You know that the a fan (like the pc fan that cools the processor) needs a quantity of energy to work. The most usually are 12V to work Ok. Some days ago, I have seen a video where a guy moves a fan to make energy. That guy used the help of a blowdryer to move the fan at a high speed. The video shows that moving the fan at high speed you can make power to run a device (in the video was a led). So, if you have a motor, you can have a generator if you inverse the process (you move the fan). My question is, If the fan need 12V to work properly... How much energy can I obtain if I move the fan? I know that It depends of the speed that I move the fan, but I want to kno…

Hi. When a turning wheel comes to rest, there is an apparent tiny backing of the motion. Is it apparent or real ? As in a turntable, a ceiling fan, or any horizontal turning mass when comes to a stop, gives the impression of reversing.

Not sure if any of you have seen this, but below is a youtube link so you get an idea of the variety of situations you can simulate / create... Here's a link if you wish to download (only windows and Linux)... http://www.acc.umu.se/~emilk/ I really should be in bed, but another half an hour on this won't hurt

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

Edit: See this thread.

G, g, and Strong Nuclear forces.... Are these forces all the same, or are they different??? Yes I know about acceleration, but it is still a force. G from what I know is the same in all the universe yes?? Science talks about forces, but if these forces have never been seen, how then can these forces be either related, the same things, or have different values, on different planets, altitudes and etc.. As per the periodic table being involved with invisible forces, only obscures matters even more... Please pardon this, but I don't get the point, this makes no sense whats so ever...

So basically I posted the following analysis as a comment on this cat video on youtube. "At about 2 minutes in, the fan circles 4 times in 5 seconds. That's 0.8 cycles per second. If we assume the cat's spinning an average distance of a metre from the centre of the fan, that means it's moving at 2.5 metres per second. (v=2*pi*f*r) Also, the circular acceleration would be (v*v)/r, which would mean a velocity change of 6.25 metres per second every second. And so, to the cat, the pull of the rope probably feels like two thirds of the pull of gravity." What say you, Science Forums? Is my analysis valid?

I read some explanations and definitions, still do not have it clear. Any simpler wording from any of you, please? (Nuclear magnetic resonance spectroscopy) http://www.cis.rit.edu/htbooks/nmr/inside.htm http://www.scirus.com/srsapp/search?q=%22Chemical+shift%22&ds=jnl&ds=nom&ds=web&g=s&t=all From what I grabbed; when exposing an element to a magnetic field, its resonant frequency changes (shifts) certain frequency. As for Au, it is 1.712690 MHz. For Ag is 4.653623 MHz, ... Now, -That amount of shift corresponds to a fixed reference amount of field, say 7 Tesla. ? -Is the shift less for a lower intensity magnetic field ? -What …

How do physicists categorize forces such as coulombs, gravity, etc. that accumulate as the "group" of atoms increases (or density increases). Or is this just standard behavior of all forces (including strong, weak). Any thoughts? I guess it comes down to can strong and weak force exist outside of an atom's electron shell (edit: or proton, rather). Any ideas?

It s said "Dark Matter" occupies about 90% of the Universe. If it was dark we would see quite nothing from the Universe in telescopes. We wouldn't see stars nor galaxies. Actually it should be "Transparent Matter"!

Interesting video on how voltage passing through an electric wire is being compared to waves passing through water.. The whole thing is worth watching but at 10:25 is where the results of the experiment is really starting to show..

Hi all, I am becoming increasingly interested in the science and mathematics and was wondering if you could offer some advice. I didn't do well at school (Lazy, uninterested) however later in life have found I am very interested in a number of areas. I'm studying a distance course in Astrobiology via Coursera (Uni of Princeton) but find myself wishing I'd paid more attention in biology, chemistry and physics. I have been teaching myself mathematics and am at a good standard of pre-calculus (confident with trig and algebra, exponents etc). Can anybody recommend a book which gives a good (but probably relatively shallow) introduction to the key sciences upon w…

Could this be true? Wouldn't the magnetic field strength have to be far higher if it would work at all?? Gas Magnet

To start, 'microwave' is not a verb, but less bad than 'nuke'. And irradiate sounds weird. To the point, the 'five minutes' <but your microwave power can vary, so adjust the time accordingly> Should it properly be instead of a timer, a Joules counter/setting dial ? Or Kilowatts-minute ? Could it lead to better recipes instead of the imprecise legacy? A tree that grew crooked, crooked stays. No 'irradiate 200 Joules' setting to your yesterday pizza?

I've seen a number of formulae in electromagnetism refer to the "number of turns in a wire;" not some function that converges at infinity, but rather linear proportionality. (To things like magnetic field, magnetic inductance, etc...) I get that, in practice, once a current carrying wire generates a magnetic field, this creates a back emf and decreases current to some equilibrium level. But in that initial instant; when the current begins to flow; does this mean you could have a theoretically infinite magnetic field/inductance/etc... with enough turns of wire?

Hello Everyone.I need to measure "surface electrical charge(charge density)" of a paperboard. Do you know the name of instrument that I have to use?

i just want to know about tachyons as a layman right from the beginning

"The Equation Breaks Down" I remember hearing this statement in a physics documentary some time ago. I presume it to mean that an equation which gives valid or verifiable predictions within a certain range, once that range is exceeded, produces incorrect statements or values (for example Newtonian Physics cannot describe activity on a quantum level, therefore its mathematical predictions would "break down"). That an equation should "break down" on one level but remain true on another would seem to mean that the equation is not in fact true or absolute. I would like to know any other current mathematical examples in Physics where equations appear to collapse or produce…

This literally hurt my head when I read that statement in a book, the book was trying to prove that Physics rhymes historically to the point of the rhyme itself being the science instead of the Physics that we normally would pay attention to. In the first 3 pages of the book he writes in big bold letters dramatically, “ ‘THE YEAR OF 1-DERS’ SHOWS THAT ‘PHY-6’ BEGAN IN YEAR ‘1-666’ WHEN ‘NEW-TON’ CREATED HIS ‘NEW’ LAW OF ‘TON’! ” When I went to check if that was true it checked and I was scared. Have you ever heard anything like that before? And when younger more naive people here that statement this younger generation that is into entertainment and ra…

Intriguingly, here is a Google Deepmind paper (September 2016) that like the paper of mine, entitled "Thought curvature" (May 2016), considers combining translation invariant, and translation variant paradigms (i.e. disentangling factors of variation), particularly in the regime of reinforcement learning, causal laws of physics, and manifolds: https://arxiv.org/abs/1606.05579 Separately, "Thought curvature", describes algebra that utilizes super-manifolds, instead of merely manifolds. Given particular streams of evidence..., is a degree of the super-manifold structure a viable path in the direction of mankind's likely last invention, Artificial General Intellige…

quote from the Wikipedia article on "digital physics": http://en.wikipedia.org/wiki/Digital_physics I haven't read the article in detail, although as I understand it, one version (not the original) was given by the great American physicist John Wheeler. Looking at the summary of the article I also see that an extreme version of this is "The Matrix", that we're in the middle of super-gigantic simulation. Without going into detail, I have a notion this is a wrong-headed notion because of Godel's theorem , but I would like to hear from more knowledgeable people than I about the pros and especially cons of this idea.

So my question to you is : Is there any element that if a stimulated using a wireless frequency, would create heat/energy? I.E. : If gold created heat/energy when stimulated in said way, would that heat/energy be able to be converted into electricity, for example. *Note that I am just a stupid 16 year old who doesn't know anything, so don't hate on me too bad if what i'm saying isn't making sense...*

Someone asked a question the other day that made me realise that there seems to be a parallel between the Heisenberg uncertainty principle (HUP) and Noether's theorem. For example, one conjugate pair of variables in the HUP is energy and time. While in Noether's theorem, the conservation of energy is related to time symmetry. Another conjugate pair is momentum and position. And the conservation of momentum is related to spatial translation symmetry. I assume this is not just a coincidence. So is there a deeper reason? Is Noether's theorem the reason why these are conjugate pairs?

Is there any way to magnetize aluminum or at least repel aluminum in any way using electromagnetism? Could eddy currents somehow accomplish this efficiently?

Alright, so today in my science class we attempted to measure the weight of my teacher's 2006 Honda Civic. He claimed that by calculating the surface area of each of the tires, and the PSI in each of the tires, we could find the weight of his car. We used the formula P (Pressure)=F (Force)/A (Area) rearranged for this lab: F=PA Because we only had tire gauges that measured PSI and not Pa, we went with standard units (Inches for length/width, PSI for pressure, lbs for weight). The weight came out to be around 4000lbs, obviously WAY too high for a Honda Civic. The posted weight was 2628lbs. However, the measurements we got could NEVER have worked out because t…