3,479 reputation
619
bio website
location Netherlands
age 41
visits member for 4 years, 8 months
seen Jul 16 at 14:22

Jul
15
answered Why the absolute temperature used in radiation equation of Stefan Boltzmann law ?
Jul
2
comment How to emulate 40ft (12 m) of water?
Too thin internally, causing the Capillary effects I mentioned. I don't think the straw will burst, simply because the pressure won't be very high.
Jul
2
comment How to emulate 40ft (12 m) of water?
@DoubleDouble: As long as you don't get capillary effects, no. A drinking straw is probably too thin, though.
Jul
2
comment How to emulate 40ft (12 m) of water?
@Vajura: Indeed, that is the whole point of the method. Lots of pressure, limited volume, limited energy.
Jul
1
awarded  Nice Answer
Jul
1
answered How to emulate 40ft (12 m) of water?
Jul
1
comment Why do atomic clocks only use caesium?
@MasonWheeler: Not an electron, a cesium atom, and its particular transition has a frequency of 9,192,631,770 per second. That's not exactly a round number.
Jun
26
comment How much a juice maker increases the temperature of the product?
Also, the 2500/4.17 has units 2500J/4.17 J/K g = 600 K g (Kelvin grams) or more conventionally 0.6 K kg (Kelvin kilograms).
Jun
26
comment How much a juice maker increases the temperature of the product?
I suspect the 500W is a peak power figure, which is needed when the blender is trying to digest a particularly tough item. Apples probably aren't the toughest fruits you'd want to squeeze, so you might need only 250W on average (1250J).
Jun
11
comment Sound source not in a straight line with the sound receiver - does that make a difference?
It may be good to realize that sound is a longitudinal air pressure wave. That is to say, sound is air moving back and forth. But just as a fan cannot push air straight forward, so can't sound.
Jun
10
comment What would put a harddisk drive (HDD) under 350G's of force?
@NateEldredge: The calculation becomes quite a bit harder when you assume it hits the ground corner-first. It's quite likely that the different corners hit the ground over a much longer period than 2 ms.
Jun
10
comment Is half-life a statistical average of variable decay times?
@Skyler: The "no memory" property does apply in all rest frames.
Jun
9
comment Is half-life a statistical average of variable decay times?
@Josef: Particles have no memory. "Just created" doesn't give them a longer life expectancy.
Jun
9
comment Is half-life a statistical average of variable decay times?
It helps to realize that a single particle cannot half-decay. At t=0 you observe the original state and at some t>T you observe the decayed state. This time T is just the time it took the particle to decay from the moment you started observing it, and it's not the half life. This shows that you cannot extrapolate the half life concept to a single observation.
Jun
7
comment If a microwave oven disk rotates to warm up food, why doesn't it go up/down/sideways?
@ZevSpitz: Significantly more complex, for two reasons: the source must be connected by a microwave pipe which doesn't leak waves (they're rather dangerous). This is problematic with a flexible joint. Secondly, the microwave source operates at a high voltage, which requires wires with decent isolation (not really flexible). It would be far easier to alter the standing wave pattern by moving passive reflectors inside the oven.
May
21
comment What speeds are “fast” enough for one to need the relativistic velocity addition formula?
Note that when we write "24 km/s or so", we already imply that our tolerance for input errors is several %. "24 km/s + 5 km/s = 29 km/s", with the error margins dominated by the input error regardless of the formula used to add speeds.
May
12
comment Why isn't the color of a molecule a combination of the colors of its component atoms?
It may be important to point out how those electrons interact: they can't be in the same state. Two electrons can share an orbital if the spins are opposite. In theory, electrons repulse each other, but around atomic nuclei (with all the protons) this isn't so important.
May
10
comment Physics in the movie 'INTERSTELLAR'?
(BTW, this is the plot of the 1977 novel Gateway by F.Pohl)
May
10
comment What stops the middle point of a power line from falling?
@GMB: Have you checked Wikipedia? It's fairly easy to see that the horizontal part of the tension factor cannot change as the two horizontal forces on either end of the chain are mirror-symmetric and gravity is vertical.
May
10
answered Physics in the movie 'INTERSTELLAR'?