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visits member for 3 years, 11 months
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Jul
12
awarded  Commentator
Jul
11
comment Need mathematical explanation for different musical notes sound different on different instruments
This is a question of physics, or maybe biology, not mathematics.
Jun
6
answered Thought experiment - would you notice if you fell into a black hole?
Jun
1
comment How electrons move so fast in a electric circuit?
@paul: That doesn't mean any individual electron ever drifts over a distance anywhere near that size. In fact, wikipedia says that they only travel a couple micrometers.
May
19
comment Does General Relativity imply loops in space?
"Cylinder" is probably a better description than "loop" for what people think of by the word "orbit". It's the cross sections of the cylinder (e.g. what you'd 'see' in an 'instant of time') that are loops.
May
17
comment How electrons move so fast in a electric circuit?
This post has two questions: the explicit "how do electrons flow through the wire" and the implicit "how does electricity work?" It's disappointing that the only answers to the explicit question are downvoted, and the upvoted answers only address the implicit question, and appear to be about direct current rather than alternating current.
May
17
comment How electrons move so fast in a electric circuit?
Am I missing something? This is an alternating current, so the electrons are just jiggling back and forth, not flowing through a 'tube'.
Nov
4
awarded  Supporter
Jun
9
comment Moon's pull causes tides on far side of Earth: why?
@Muhammad: You're forgetting that there's a big rightward arrow that all of these should be added to to get the actual gravitational attraction: none of the attraction is in the "opposite direction". The diagram above has simply subtracted off the big rightward arrow so we can more easily see the differences: in particular, how it looks from an earth-centered reference frame.
May
22
comment Why do lasers cut? Is this a case of light acting as matter?
@Keavon: ... thus you are probably thinking of "melting" rather than "burning".
May
1
comment Why does ice melting not change the water level in a container?
@Jodrell: It's the big sheets of ice sitting on Greenland and Antartica that everyone worries about.
Oct
9
comment The inner workings of the Olbers paradox
@Mark: I meant it's plausible, but nonobvious, that the effect of scattering washes out.
Oct
9
comment The inner workings of the Olbers paradox
@Mark: But such objects will still scatter the light. It's plausible, but nonobvious (to me), that this effect washes out.