J.C.MacSwell

Just a joke, but didn't know there was anything behind it. More massive things fall faster etc. Intuitive but untested in Aristotelian Physics etc.

Yeah, I guess that Greek urned it...

Surely they've shaken that stereotype by now...

OK, so you are assuming no losses due to friction and disregarding the rotational energy...an idealized case. So you know they are both at the same speed at the bottom, and that Y has a slightly longer path, though it is not defined exactly it is a smooth curve. Which one accelerates faster at the start? What is the speed of X, halfway along its path? How much faster is Y moving, halfway along it's path?

Same frame?

I assume this is homework. Can you tell us your answers for c) and d). I think that may help with answering b).

How does your conjecture explain gravitational anomalies, deviations from the idealized case, caused by such things as changes in terrain and density near the planets surface? Current theory explains it quite well and is used in mining to find ore deposits etc.

Thank God Planck did not take any of that into consideration.

The galaxy problem lies in the fact that the assumptions used to produce that formula, taking into account all the apparent mass in the galaxies, don't seem to hold true. (so Newton's law of gravitation wasn't matching the evidence) The speeds of rotation were calculated from the difference in the redshift (generally) relative to that of the galaxy as a whole. So one "snapshot" could provide a lot of information given the right set of assumptions and measurements. I don't believe they were noting any displacements over time to get the data.

That, and the events have to be adequately separated spatially. No one will interpret an effect to have preceded a cause.

Thanks, but I'm not Mach, and as far as I know it is unproven conjecture....metaphysics that may have helped toward the General Theory of Relativity. Your statements seemed to be directed along similar lines of thinking.

Sounds a little like Mach's principle (or conjecture) http://en.wikipedia.org/wiki/Mach's_principle

Hey...they laughed at Edison... So far we have: 2 votes: Einstein Feynman Maxwell 1 vote: ajb (voted for himself) Galileo Newton Dirac Walter Lewin Leonard Susskind Hawking Archimedes Watt Manfred Curry Sagan "Honourable" mention (by himself) to Swansont Disclosure: Although in a Science Forum, poll is not a scientific one, some have voted more than once, so far a pretty small sample size...but looks like we have a couple of our own among the favourite scientistists of all time...

Have you driven a car and turned on your headlights? What did you see? Relative to some inertial frames you were almost at lightspeed, but at light speed in none.

Must include the guy in my avatar, a young James Clerk Maxwell Feynman, for the wit as well as the science Always liked Archimedes, James Watt For a lesser known pick, Manfred Curry, scientist, inventor and yachtsman

You need to balance the pressures on the returns from the filter. If you get it close it should then self regulate...if more goes to one the level gets slightly higher and the head pressure will restrict extra flow to that jar/tank. If one jar is farther away you may need a larger tube to that jar/tank, or restrict flow to the other. You can use adjustable valves for fine tuning or simply pinch the tubing with an adjustable clip.

So..tea it is then...

This is the both the key...and in 514's example potentially misleading if not understood in the right context. In every day language it makes no sense.

Gravitational acceleration should not be a problem unless tidal forces become significant, unless of course something lies in your path...like, say, the Earth...

You can calculate as precisely as you wish, it won't make any difference. The results will not be accurate if based on the premise that you can transfer energy and momentum to one frame from another, using the same numbers, and not allowing for the difference. It might work in some universe, where you might want to patent your invention, but it won't work in this one. edit: When I do a thought experiment, or a mathematical model, that show results that violate physical law (it is not that uncommon), I know I have made a mistake...time to check the math or assumptions

Is it? With respect to what frame?

Then that is where it happens. You can pinpoint it further for us...it is your design, though again, the forces involved are normally too small to be of any consideration...same with the relativistic mass. Taken together they add up to nothing, which explains why Newtonian mechanics is so useful on it's own for analyzing the vast majority of applications.

If the energy is inputted from a different frame from that of the disk, then yes. Do you think that adding mass to something will change it's velocity? Compare your answer to mine above.

Because that energy has momentum/inertia. If it is coming from the container, or the other disk pair, you need to account for it. It is the same transformed energy you are pointing to when you want to account for it when it is relativistic mass.

Idealized cases for the energy transfer; referenced to the COM frame If the energy for spin up comes from the pair itself, the momentum of the disk pair doesn't change, loss to battery equals relativistic gain from spin, so it won't work If the energy from spin up comes from the container, the momentum of the disk pair doesn't change, loss of velocity balances relativistic gain from spin, so it won't work If the energy from spin up comes from the opposite pair moving in the opposite direction, the momentum of the disk pair changes, but in fact the spun up pair loses some momentum; but is balanced by the changes in the other pair, so it won't work, not even backwards but you can always calculate in newtonian terms for one part of the cycle, and include the extra relativistic momentum from the spin on another part of the cycle, without worrying about how it got there...