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location Sunnyvale, CA
age 29
visits member for 3 years, 11 months
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Aug
30
comment Why do I always hear remote train horn at night?
The same thing happens some places even when the tracks aren't needed during the day for public transit; running trains at night avoids needing to hold up as much traffic at crossing.
Jul
23
comment Which ball touches the ground first?
@ivy_lynx Your next comment still says that the force is different so the acceleration will be different. Have another look at my comment: I explicitly explained how the different force results in the same acceleration. (Feel free to change $g$ to $a$ if it makes it more obvious.)
Jul
23
comment Which ball touches the ground first?
@ivy_lynx More specifically, you said "replace g with the Newtonian expression". If you think about what the Newtonian expression actually is, remembering that g is what you're calling the acceleration due to gravity, $F = m g = G M m / r^2$, thus $g = G M / r^2$, and it depends only on the radius and mass of the earth, not on the mass of the object you're dropping.
May
3
revised What properties make a good barrier for microwave (oven) radiation?
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May
3
comment What properties make a good barrier for microwave (oven) radiation?
Thanks for all the explanation! I'm really trying to ask about what specific properties are necessary here, like material, mesh spacing and wire diameter. The most useful solution would be something light and flexible, that can easily be shaped, but if there's too little metal, presumably you'd get undesirable resistive heating, and maybe some microwaves passing through?
May
3
revised What properties make a good barrier for microwave (oven) radiation?
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May
3
comment What properties make a good barrier for microwave (oven) radiation?
@freude Sure, that's why I mentioned metal. But how much does conductivity matter - could it be something cheaper than copper? What about mesh spacing and wire diameter? And how does arcing fit in?
May
3
asked What properties make a good barrier for microwave (oven) radiation?
Jan
29
comment How to brake 'beautifully'?
@EnergyNumbers I wrote something up; no plots, pictures or equations for now, just qualitative explanations. I'll try to polish when I'm less busy.
Jan
29
revised How to brake 'beautifully'?
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Jan
29
answered How to brake 'beautifully'?
Jan
29
comment How to brake 'beautifully'?
Okay, well, then what I'm saying is that your model is missing the dominant force at the end of braking. (And of course, we do also feel jerk horizontally, which is why that force is so noticeable.)
Jan
29
comment How to brake 'beautifully'?
I think the part you're missing here is that when you stop in a car, the car shifts forward a bit on the suspension. So it's actually really important to approach zero acceleration, so that the car is already sitting in its final position when you stop, avoiding that bit of a jerk back as the springs move the car back.
Oct
26
comment Why is light called an 'electromagnetic wave' if it's neither electric nor magnetic?
This is a great demonstration of the photoelectric effect, but the photoelectric effect doesn't exactly demonstrate that light is electromagnetic. It could just be some other kind of particle that's capable of knocking electrons loose.
Oct
26
awarded  Critic
Oct
26
comment Why is light called an 'electromagnetic wave' if it's neither electric nor magnetic?
This is of course completely correct, but I don't really think it answers the question, which is implicitly asking why sunlight doesn't appear to be electric or magnetic, particularly in form of the more everyday forms of electricity and magnetism.
Oct
26
revised Why is light called an 'electromagnetic wave' if it's neither electric nor magnetic?
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Oct
26
awarded  Yearling
Oct
26
revised Why is light called an 'electromagnetic wave' if it's neither electric nor magnetic?
added 43 characters in body
Oct
26
answered Why is light called an 'electromagnetic wave' if it's neither electric nor magnetic?