# Kedas

Senior Members

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• Birthday 01/26/1973

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## Profile Information

• Location
Belgium
• College Major/Degree
Engineer Electronics

• Molecule

21

1. ## Help! Moment of inertia??

Not sure why you talk about 2D formula's, there are none for MOI. You know very well that it is not possible to have a mass without a volume. Maybe on some quantum level but I'm sure these formulas don't apply there. Even if the height is only dh it would still be a cylinder. And simplifying the formula for certain applications is ok for me but that still doesn't mean that a circle has a MOI. Unless you like to change the definition of a circle that it has a height. What you are saying is as interesting as saying that a circle (r>0,L=0) does or doesn't have an electrical resistance. if there is no distance to travel there no meaning in the word electrical resistance.
2. ## Help! Moment of inertia??

From what I read genralz isn't interested in math for the math. The simple fact is that the MOI formula requires a mass to have some meaning. Yes you can make up an mass that has no meaning, I don't care. genralz, in case you mean MOI of a cylinder or cubiod etc. here are the formula's. http://en.wikipedia.org/wiki/List_of_moments_of_inertia
3. ## Help! Moment of inertia??

A square or circle doesn't have a volume/mass therefore it has no moment of inertia. used if you want to know how much energy is in there. You mean http://en.wikipedia.org/wiki/List_of_area_moments_of_inertia "The second moment of area, also known as the area moment of inertia or second moment of inertia " used if you want to know how easy it will bend and where.
4. ## Physicists resolve a paradox of quantum theory

I didn't find the news forum to post it in. Anyway, I was wondering if this is related to the Heisenberg's Uncertainty Principle or am I understanding it wrongly?
5. ## Physicists resolve a paradox of quantum theory

http://www.physorg.com/news151164690.html
6. ## Spooky wave interference

http://www.physorg.com/news141394051.html
7. ## Chance to see a major asteroid impact. On Mars.

no impact: http://neo.jpl.nasa.gov/news/news156.html They must have used their gravity beam ;-)
8. ## Chance to see a major asteroid impact. On Mars.

If they don't know yet if it will impact mars then a close fly by could change the orbit of it so it is on track to make a collision with an other object, maybe earth in 2011.
9. ## Chance calculation

Thanks uncool. My weird 'feeling' example feels much more right now
10. ## Chance calculation

Thanks for the explanation 1-((n-1)!/n!) looks more right because it doesn't look too simple
11. ## Chance calculation

It looks right for n=2 and n=3 but n=1 should be 1. and if n is very large than the change that at least one stays at its current position is very high. So if I have a cube of water and give it a good (random) shake. Then I can say it is very likely that at least one molecule arrived on it's previous position. That sounds a bit weird?
12. ## Chance calculation

If you have an ordered list of numbers and you randomly change them what is the chance that at least one number will stay on its previous position? Or more practically if you give everyone a number and you let them blindly pick a number. What is the chance that at least one persons picks his/her own number again.
13. ## Evolution more predefined than we think

Evolution is deterministic, not random, biologists conclude from multi-species study A multi-national team of biologists has concluded that developmental evolution is deterministic and orderly, rather than random, based on a study of different species of roundworms. The findings are reported in the latest issue of the journal Current Biology. http://www.physorg.com/news114700358.html So random changes with natural selection is not reality, but more like a smart change.
14. ## Water forms floating 'bridge' when exposed to high voltage

From the page: How high the static voltage has to be or how pure the water has to be is not mentioned, but they do say that dust is probably a reason that makes it unstable It's like liquid ice.
15. ## Water forms floating 'bridge' when exposed to high voltage

http://www.physorg.com/news110191847.html It's cool but weren't we suppose to find something like this about a half-century ago?? I'm mean you don't even need a lab to reproduce this experiment.
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