Recent content by makc

is it not the same as with gravity assist, these constraints should apply to spaceship and black hole together? I guess I'm asking if falling body can borrow some of black hole energy.

As far as I understand, a spaceship going around rotating black hole should gain additional acceleration due to frame drag. Right? So, would there be max speed gain, like in gravity assist, or could you accelerate infinitely? Thanks.

but you can't play this card with gravity, can you? whatever falls down on the planet, planet's gravity does not get weaker (even if we ignore additional mass of things that fall). you can keep "spawning" objects at some distance, and it will pull them to the surface, ad infinitum.

here's simplified version of experiment: we have a glass tube, a small piece of glass which friction would be less than capillary forces, and mercury droplet. will it move to the right, and why not, if no? [PLAIN]http://img43.imageshack.us/img43/962/80143546.jpg

Thanks Andy, Well, this was just my intuition that, if intermolecular forces cause liquid to move, they do some work and so something must lose energy... why not molecules themselves? and if so, the overall effect would be cooling. but then, I thought about magnets and gravity and how they move...

(if eventual diffusion bothers you, imagine that we embedded very light "cork" into the water that splits it in two halves that cannot communicate... this is just a matter of clever enginering, right? the question is, what's there to stop the motion) variation 2: imagine a tube made from...

another question for capillarity effect: imagine circle tube horizontally alligned, with no air inside and one droplet of water. since its surface tension is equal on both ends, it doesn't move anywhere. now if we were to sprink small amount of soap on one of its ends, the surface tension there...

that's kinda brings another similar question, if we bring metal closer to magnet from above, it will jump up and stick to it. obviously, some work has been made by whatever electromagnetic forces there are, so you would expect this energy to come from somewhere. I guess the notion of...

ok, let's begin with simple things: seems like a right picture to start with. there's non-90° angle, and so net gain of all the forces is upward (and stays so, until enough water is lifted, and gravity cancels it). but, why the hell there's non-90° angle to begin with? why, out of sudden...

some image or video on what's going on at the edge would be perfect.

can we store an energy in surface tension, to make liquid go as high as we want? can we extract an energy from surface tension to light up lightbulb, and so produce a liquid with empty surface tension :D I mean, just these two words by themselves do not really explain anything.

I just recently had a conversation, where we discussed if liquid is getting colder as it moves along thin tube where it "normally" wouldn't. And if it does, doesn't it mean we have a system that makes things colder without warming anything around it? Which I thought wasn't possible.

Trying to implement QR decomposition using Givens rotations, I calculate G1 to zero n32 of original matrix A, then G2 to zero n31 of G1 * A, then G2 to zero n21 of G2 * G1 * A. Residual matrix, R = G3 * G2 * G1 * A comes upper triangular as expected, so I believe my code is correct. Looking...

speaking about "no crackpot theories" remark, are you also going to filter out these out of google ads?

maybe it is also interesting how could there be an evil mathematician? "Look, batman, now I will convolute every citizen in Gotham"