You have been confused by the flawed ball-on-rubber-sheet analogy. A surface formed like this rubber-sheet doesn't represent curved space-time, just...
Linear polarization is rarely used in 3D today, because of the head tilting problem. Circular polarization is explained here:...
I know: 1) green / red (or blue / red) 2) linear polarisation 3) circular polarisation 4) shutter glasses Turning your head by 90° should mess up...
You're welcome. To answer your question: "In a black hole is a sphere even a sphere anymore?" We still call it "sphere" but it has different...
Here is an overview: http://en.wikipedia.org/wiki/Non-Euclidean_geometry
A straight line is a geodesic. A geodesic is a generalization of a straight line to non-Euclidean spaces. A straight line is a special case of a...
It would be a very close race.
That is correct. Although it would require a high performance boat. Most modern sail boats can make some upwind progress by tacking (beat the stream...
Good, now the bonus questions in post #26.
Yes, but any downstream progress you make relative to the water means you are faster than the stream. In heat two you can't do anything, just drift...
[spoiler] And now the bonus question. Origin asked for the following clarification: Questions: Could a sailboat possibly sail upstream in the...
You are both assuming that the sailors are lazy. As was clarified they are actually trying to win the race.
So which race will be faster?
Why?
What about Baldeee's idea?
So which heat would be faster then?
What is missing? Note that the question doesn't ask to provide exact times, just which conditions allow faster travel downstream.
Just because you sail as good as possible, doesn't mean you have no drag at all. There definitely is some drag, if you move relative to the air.
Assume they always sail in the optimal way according to the conditions. They use modern, efficient racing yachts What would be the optimal rig for...
Despite the different conditions? That is true for the afternoon. But what about the wind push in the morning?
Separate names with a comma.
