8,024 reputation
1728
bio website en.wikipedia.org/wiki/…
location United States
age 70
visits member for 3 years, 6 months
seen yesterday

BS Mechanical Engr.
PhD CS(AI)
CS Prof (4yr)
Numerous consulting jobs.
15 yr at http://www.pharsight.com
Published book on CS & several articles
4 kids, 2 grand
Pilot(student)

P.S. The picture is a Beta-prime distribution. It shows the program speedup factors you can get if you see a problem twice in 2, 3, 4, and 5 samples.


Dec
10
answered height of dam to allow certain flow rate
Dec
8
comment How to approximate lag of roll of a bird (or RC airplane)?
@Yeti: You're probably only able to estimate an approximate value. There's guesswork no matter how you do it.
Dec
6
answered How to approximate lag of roll of a bird (or RC airplane)?
Dec
3
comment Gravitational field intensity inside a hollow sphere
I like Qmechanic's answer, but my own intuition is this: suppose the shell consists of a lot of small "moons" covering the shell. You could be close to one and feeling its gravity, and the ones "across" the way have gravity that falls off at $d^2$, but the number of them increases with $d^2$, so they are just as powerful as the one you are next to.
Dec
3
comment Calculating the force required to lift a weight with a screw
He's ignoring friction, so it's just an energy balance. The energy put into lifting the weight is what? 2000 lb * 1 inch = 2000 inch-lbs. That handle must be pushed 1260 inches to get the same energy, and 1260 inches * 1.6 lb ~ 2000 inch-lbs. What's this dimensional analysis you're talking about?
Dec
2
comment Why is a thought experiment a valid way to prove anything?
@Albalma: Next to Feynman's lectures, this is my favorite book on relativity. The author was teaching relativity in a continuing-ed class where people were math-phobic, so he does a great job of making it accessible.
Nov
30
comment Why is a thought experiment a valid way to prove anything?
@Albalma: I agree - dogmas and stigmas are bad things. I'm in favor of skepticism. Not only questioning of positive results, but questioning of negative results. A perfect example is "cold fusion". If on the other hand you're talking about global warming, skepticism is a good thing, but using it as an excuse to do nothing and just let the hammer fall is poor wisdom.
Nov
30
revised Create air stream from heat
added 56 characters in body
Nov
30
answered Create air stream from heat
Nov
30
revised Why is a thought experiment a valid way to prove anything?
added 294 characters in body
Nov
30
answered Why is a thought experiment a valid way to prove anything?
Nov
28
comment Why can't we fly?
We can fly
Nov
25
comment When an aircraft flies over, glass window vibrates…Infrasound?
Just my guess - there's no reason the noise can't go into frequencies below what you can hear (about 20 hz). Of course if it makes your windows hit their frames, those clicks will be at a higher frequency so you can hear them. Nothing strange about that.
Nov
22
comment Torricelli with constant vertical drain speed
I don't understand the question.
Nov
21
comment Why are flight feathers asymmetric?
I'm guessing it's to match the pressure distribution, which is greater toward the leading edge. Whether the wing is swept back or not is not the issue.
Nov
17
answered Is more lift always better?
Nov
13
comment What exactly are light waves?
It's a good idea to study Young's double-slit experiment. I like to think of it as a wave of alternating electric and magnetic fields, but it also acts as a probability amplitude wave of a photon appearing. So when the waves interfere, they're changing the probability of photons appearing.
Nov
11
comment What prevents this rotational perpetuum mobile from working?
The two red wheels at the bottom are turning against each other. If they have friction, them all the kinetic energy turns into heat energy. If they are gears, then the wheels can't even start. $w_1$ has nothing to do with it.
Nov
7
comment Trajectory of a bomb dropped from an aeroplane
As @Omen said, we're trying not to be a homework completion service.
Nov
4
comment hydrodynamic entrance length [developing flow]. Non-native speaker needs some help
I think your English is not bad. I think the sentence is fairly clear, although I don't understand the content.