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location Australia
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visits member for 2 years, 4 months
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18h
comment Is speed of light and sound rational or irrational in nature?
And of course, in the geometric unit system, c=1
1d
answered Why is emf equal to PD when circuit is “open”?
2d
comment How does weight add up to press on things?
It's not "gravity from the top block". Instead, it's the gravity from the earth on the blocks that creates the extra weight. Remember that weight = mass X acceleration. Also remember that Newton said F=ma. Hence, doubling the mass also doubles the force on the paper.
Jul
15
comment Day/night cycle in Greenland
I know it's more complicated than my explanation. For another variation, the solstice date varies from year to year. But hopefully, this gives the asker some idea.
Jul
14
answered Day/night cycle in Greenland
Jul
10
comment Black holes attracting each other
The way I see the question, it is not about new theories. I think the asker does not understand how gravity works, and asks for clarification. That is quite legitimate.
Jul
10
comment Black holes attracting each other
Gravity works infinitely far away. However, it weakens with the square of the distance (if you're 2 times further, gravity is 4 times weaker). Also, gravity only works in a straight line between the bodies. If one (or both) moves sideways, that sideways movement is not affected. That is how planets orbit the sun: they want to keep moving in a straight line, but the sun pulls them so their path is bent into an ellipse around the sun.
Jul
10
answered Black holes attracting each other
Jun
30
comment Why aren't all photons virtual particles even in the “vacuum” of empty space?
+1 One of the clearest explanations of the wave/particle duality I've come across.
Jun
18
comment Hydrostatic pressure - doesn't density vary with depth?
At 1km depth the pressure is about 100 atm. Hence water will compress 4600 ppm or 0.46%. In most calculations you will not have to worry about it.
Jun
17
answered Hydrostatic pressure - doesn't density vary with depth?
Jun
2
comment Any real life demonstrations of radioactive decay?
Any observable mass that completely decays or changes into another, different looking element over a couple of weeks, would emit enormous amounts of energy (radioactivity), and destroy the camera in the process.
May
28
comment Is Newton's third law always correct?
@Sachin Newton's third law is obeyed, because you can only apply as much force as the wall will take. If you try to apply more force, you can't because the wall disappears. Hence action = reaction.
May
28
answered Does a conductor need to touch the battery terminal for electric field to be set up inside it?
May
28
comment Is Newton's third law always correct?
@LCD3 You need to deliberately try it: apply the brakes gently, and gradually increase pressure. At the point where the wheels lock, the brakes suddenly lose effectiveness, and that makes it feel as if the car shoots forward. The reverse effect happens when you accelerate until the engine hits the rev limiter: it feels as if you've hit a wall.
May
28
answered Is Newton's third law always correct?
May
19
comment Wrapping plastic in aluminium foil to protect it from heat
The insulation effect of Al foil is minimal: Al is a very good conductor of heat (as well as electricity).
May
12
comment if the universe is flat does it mean it exists only in our mind as math?
"Flat" is used as in "Euclidean Geometry". In other words, there is one and only one line through a point that is parallel to another line. In curved universes you can have none (spherical geometry) or more than one (hyperbolic geometry).
May
3
comment How loud is the thermal motion of air molecules?
If it is about sound then my answer stands: the sound is way above the audible range. Assuming it is white noise, someone may be able to calculate the amount in the audible range, but that will be minuscule.
May
1
comment How loud is the thermal motion of air molecules?
I wrongly assumed the question was specifically about sound. On re-reading it, I realised that it could also be about microwave radiation, in which case my answer is not really relevant.