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age 20
visits member for 2 years, 2 months
seen 40 mins ago

7h
answered Newton's law of resistance
9h
comment Maxwell's Inspiration to think about fields
I think this answer takes that one sentence of the question too literally? Yes there are atoms, but there are also fields with a reality/effect of their own, and that's a big switch from saying that there are atoms with some instantaneous action at a distance force.
2d
comment What do people actually mean by “rolling without slipping”?
@Muphrid I think I will. But come to think of it, that the center of the disk travels $2 \pi/9$ is perfectly expected, so maybe the statement is true if "travels one circumference" refers to the center of the disk.
2d
comment What do people actually mean by “rolling without slipping”?
(with "s" being the arc length movement of the point of contact with the curve)
2d
comment What do people actually mean by “rolling without slipping”?
@Muphrid I included the overall distance travelled by the point of contact! I'm just looking at rolling without slipping on curved surfaces and many online solutions write $r d\theta=ds$, but I'm pretty sure (citing my example above) the correct version is $rd\theta=(1-kr)ds$, where $k$ is the curvature of the surface. Actually I derived that formula using the "a point in contact with the ground is momentarily stationary" condition. I'm mostly posting this for a sanity check.
2d
comment What do people actually mean by “rolling without slipping”?
@Muphrid, see: mathandcode.com/img/diskrollnoslip.gif would you agree that this example shows that your bolded sentence isn't true on non-flat surfaces? It illustrates a circle radius $8/9$ rolling inside a circle radius $1$. The circle rolls an angle of $2\pi/8$ while its point of contact with the ground travels a distance $2\pi$ and the center of the circle travels a distance $2\pi/9$ (not $2\pi/8$).
Nov
26
comment Why is cross section inversely proportional to wavelength for interstellar scattering?
Hookean springs have $F\propto x$, though $x$ and $F$ are different units. The unit conversion is introduced in the constant of proportionality $k$. $F=kx$.
Nov
25
revised How to reconcile these two approximations?
deleted 14 characters in body
Nov
24
comment Do bad clocks measure proper time?
Could you copy the definition of good versus bad "in the sense of MTW §1.5"?
Nov
22
comment How does a giant walk-in fridge maintain a thin temperature gradient at the entrance?
@WetSavannaAnimalakaRodVance Thanks for that!
Nov
22
answered How does a giant walk-in fridge maintain a thin temperature gradient at the entrance?
Nov
21
comment How does a giant walk-in fridge maintain a thin temperature gradient at the entrance?
Is there a wind curtain? (A box/rail above the door which blows a wall of air down. They're present at many store entrances)
Nov
20
comment What is the physics of a spinning coin?
related: physics.stackexchange.com/questions/68676/… and mathandcode.com/disk I wanted to solve this problem in full generality. So my solution is undoubtedly more complicated than it needs to be. But you should be especially interested in "Partial constraint 2"
Nov
20
comment What would be the consequences of time not being “relative”
And his struggle was before he abandoned galilean relativity. You're correct that if you assume galilean relativity you can conclude that special relativity is wrong. But it seems like you're trying to show that special relativity is inconsistent in its own right?
Nov
20
comment What would be the consequences of time not being “relative”
-1 for, if no other reason, making the quote sound like it supports your post. He states in the next paragraph it was only thought by Einstein to be a contradiction when assuming Galilean relativity ("he had been assuming that the ordinary Newtonian law of addition of velocities was unproblematic")
Nov
19
comment How is strong time dilation consistent with weak tidal forces?
Mentioning spin: wired.com/2014/11/metaphysics-of-interstellar Thorne: "I went home, slept on it, did a calculation, and found that if you have a black hole that spins rapidly enough, and a planet that is very close to the last stable circular orbit, you could get the time dilation he wanted. It just amazed me." (Not that it changes your answer, just that in the movie Gargantua is in a stable circular orbit with realistic [but absurd] time dilation)
Nov
18
answered error propagation and collision in ideal gas
Nov
17
answered Structure of white light?
Nov
16
revised Physical meaning of the angular momentum
deleted 3 characters in body
Nov
15
answered Physical meaning of the angular momentum