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visits member for 1 year, 3 months
seen Mar 11 at 17:34

Jan
11
awarded  Yearling
Jan
3
answered What does the decay constant mean?
Jun
20
answered Why cellphone cameras don't have optical zoom
Jun
20
comment Why cellphone cameras don't have optical zoom
@dmckee I actually think there is a good physics-related answer for this question and was just writing one down. Basically, there are fundamental limits to how small you can make camera optics and still get acceptable noise levels, due to light quantization. Would you consider reopening?
Jun
11
comment How does irradiance behave over time?
@user61001 Yes, assuming clear sky, the irradiance on a horizontal surface will change very predictably based on the solar angle. This is the green curve in your plot. Clouds will generally cause the irradiance to be lower than this, but cloud cover alone is not enough to say how much lower it should be.
Jun
10
answered How does irradiance behave over time?
Jun
10
comment Expected behavior of the gravity under some experiment
The mass of Earth, $M$, is missing in the last two formulas, right?
Jun
9
comment How fast would body temperature go down in space?
Nice work! Yes, I should probably have made a reality check on the mass before choosing the radius (or better yet, chosen another geometry).
Jun
9
revised How fast would body temperature go down in space?
spelling
Jun
9
answered How fast would body temperature go down in space?
Jun
8
comment force applied not on the center of mass
@user25368 There is no such thing as an instant force. A force needs to be applied over some time period, however small, to make an impact. If it is examples like the one in your link that you're thinking of, it is important to understand that depending on how the mechanism striking the body works, it might not produce the same force over the same period of time for the different cases and hence the linear velocity might be different.
Jun
5
comment force applied not on the center of mass
@user25368 What do you mean by instant force?
Jun
3
comment Finite velocity at infinite distance
@joshphysics Point taken. I shouldn't have overreached.
Jun
3
comment Finite velocity at infinite distance
Infinity is not an actual point. Something cannot "reach inifinity".
Jun
3
answered Measurements and simultaneity
Jun
3
comment force applied not on the center of mass
@user25368 With displacement I just mean the distance that the point that you apply the force to moves during the time that you apply the force.
Jun
3
comment force applied not on the center of mass
@user25368 Added elaboration.
Jun
3
revised force applied not on the center of mass
further explanation
Jun
3
answered force applied not on the center of mass
May
23
comment Is there any place you can safely skydive without a parachute?
This What if?-article explores the possibilities of airplane flight on different solar system bodies. The same parameters (strength of gravity and thickness of atmosphere) are of importance for this as for the terminal velocity. It seems like Titan is your best bet. The atmosphere is four times thicker than on Earth.