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Author of Beta's Rule: "Never add to code that doesn't work."


Jun
30
comment Why does the speed of the propellant limit the speed of a space ship in open space?
@this: The same can be said of a rocket employing baking soda and vinegar, if the fuel tanks are big enough.
Jun
30
awarded  Supporter
Jun
17
comment Hydrostatic pressure - doesn't density vary with depth?
It's interesting to note that if the Pacific were ten times deeper, there might be ice at the bottom...
Jun
17
comment Do black holes cause gravitational redshift?
The edited question is clearer, but you still seem to be confusing two different questions, 1) will the ray escape? (No, it won't), and 2) will it be red-shifted? (Yes, for some observers.)
Jun
17
comment Do black holes cause gravitational redshift?
Is the source inside the event horizon, or outside? (There is now some doubt about whether event horizons actually exist, but bear with me.)
Jun
11
comment Moon's pull causes tides on far side of Earth: why?
When I take a little boy by the hands, pick him up and twirls around, his arms are pulled horizontal; that is understandable, since I am pulling them. But his legs are pulled horizontal too, even though no one is pulling them. Likewise, he pulls my arms outward from my body, but somehow my coattails are also pulled outward from my back.
Jun
9
comment Why is electric current dangerous to humans?
Few cells can survive the trip up to the boiling point, never mind the effect of the boiling.
May
12
answered Electric Field due to a disk of charge. (Problem in derivation)
Apr
10
comment Why isn't jumping from a high altitude fatal?
@Luaan: No, I would not call hitting a stone wall "friction", and I don't see how you got there. I think that "friction" is a useful term for solid-solid interaction, but it should not be extended to solid-gas interaction unless we remember that we are talking about an entirely different mechanism. I hear it used to refer to the entire process of heat generation in reentry, so the division of heat generation into "compression" and "friction" seems misleading at best.
Apr
9
comment Why isn't jumping from a high altitude fatal?
@EricLippert: I suspect that this is a "tomayto"/"tomahto" distinction. What is air "friction" if not imparting momentum to air molecules? And it's hard to do that without compressing the air.
Apr
2
comment limited number of photons problem
What's the difference between disappear (i.e. I know it's right there on the table, but I can't see it) and be invisible (i.e. when I look at the moon, I know that I'm looking at some human footprints, but I can't make them out)?
Apr
2
comment Can a magnet or a magnetic field push gravity?
What does "push gravity" mean?
Feb
23
comment Why is the moment of inertia for a hollow sphere higher than a uniform sphere?
A simpler question: why does a ring have a higher moment of inertia than a disk?
Feb
17
awarded  Commentator
Feb
17
comment Does space curvature automatically imply extra dimensions?
Zogg from Betelgeuse made a very helpful video on the subject. I cannot recommend it strongly enough.
Dec
29
comment Is it possible to “cook” pasta at room temperature with low enough pressure?
Oh, you'd be surprised.
Dec
29
comment Is it possible to “cook” pasta at room temperature with low enough pressure?
This is a very interesting half-answer. Has anyone tried it, to see if the result tastes cooked?
Oct
2
answered Angular Momentum Conservation in Gravitational Interaction
Sep
30
comment Determine resultant velocity of an elastic particle-particle collision in 3d space
Do you know how to do this in one dimension? How about two?
Sep
24
comment Adiabatic filling of a container
Some people immerse the tanks in water to cool them during pressurization. This practice is frowned upon for a couple of reasons, but the fact that it is used at all indicates that the tanks can get quite hot even during feasibly fast compression, never mind the instantaneous compression needed for the adiabatic case.