8,810 reputation
1730
bio website en.wikipedia.org/wiki/…
location United States
age 71
visits member for 3 years, 11 months
seen 7 hours ago

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.


Aug
25
comment Whether there is any relationship between the frequency of an input signal and the frequency of it's fourier transform?
What do you mean by "FFT frequency"? FFT converts between time or space domain and frequency domain.
Aug
24
comment What are the biggest reasons that Cars get higher Land Speed Records than motorcycles'?
According to the link in @Daniel's answer, some cars are 3 wheels, so it seems like it might be possible to go to 2 wheels (with skids or something for low speeds). I don't quite understand how this would be helpful, though, since it's all about engines and aerodynamics.
Aug
22
comment Determine beat frequency
First try it with two frequencies close together. Then try widening the difference.
Aug
20
comment Why does everything spin?
@rmhleo: Right. I was only answering the part of the question about classical mechanics.
Aug
17
comment Infinite Accelatation
You should make it clear that when your "high speed makes time slow down" is only true from the point of view of the observer. You do not yourself see time slow down and acceleration getting harder. i.e. it doesn't take you longer to do anything, as measured by the clock you carry.
Aug
16
comment Hard Drive Air Bearing Questions
I just googled "hard drive air bearing" and a ton of stuff came up. Why don't you start there?
Aug
15
comment Why does not a battery kept in empty space discharge on its own? If space between the terminals is empty, what prevents the electrons to flow?
And the electrons in the (-) terminal of the battery cannot simply jump into space because they are bound to the metal.
Aug
13
comment Flat throw vs 45 degree throw of a ball
If a flatter angle resulted in maximum range, then a long-ball hitter would do the same thing, but I don't think they do. They seem to go for a higher angle (not too high), and hope it lands outside the park.
Aug
13
comment Vacuum pressure equivalent in a siphon hose filled with water?
FYI
Aug
12
comment Thermodynamics about turbines
Homework!......
Aug
12
comment Simulation of a simple robot
@Ahmad: Don't look at the robot. Look at the wheels. Where they touch the surface, what is the rim speed. What is the separation between them (10 cm?, 20cm?). That's all that matters. Imagine the robot body to be big or small, in the middle or on the side, that doesn't matter. what matters is the big imaginary sheet of material that the wheels are mounted on. It has a certain rate of forward motion, and a certain rate of turning motion, and the blob of the robot body can be mounted anywhere on it.
Aug
8
comment How does a supersonic flight speedometer work?
@Wet: Right, so when you are subsonic (takeoff, cruising, landing) the indicated air speeds you should use are always about the same regardless of density altitude (altitude corrected for temperature and humidity), so there are colored bands on the airspeed indicator.
Aug
6
comment Is the Higgs field needed to explain the mass of the electron?
Thanks. That was a major confusion for me, and maybe others.
Aug
6
comment Is the Higgs field needed to explain the mass of the electron?
You say $m$ is what the Higgs mechanism gives us, but what about binding energy? Seems to me I read that the mass of a proton or neutron could be explained simply as the binding energy of the quarks it contains, without invoking Higgs. Maybe you can clarify that?
Aug
6
comment Does this analogy with matter and energy hold?
The only thing they have in common is the word "Dark". "Dark matter" is stuff out there that's heavy but we can't see it and, of course, it is equivalent to some energy, like all matter is. "Dark energy" is like a silent explosion filling empty space causing galaxies to accelerate away from each other, ever faster.
Aug
5
comment What happens to the observed thermal energy of objects at relativistic speeds?
@AcidJazz: that's a function of an accelerating observer and it refers to the background temperature, not velocity past an observer and the apparent temperature of the body moving at that velocity.
Aug
5
comment Does Earth get gravity due to it's spinning?
@Saravanan: The man coming down is not caused by spin. It is caused by attraction between earth and man. There are two things working here: Newton's first and second laws. The first law is why the spin/speed does not matter. The second law is why he comes down after going up.
Aug
5
comment Does Earth get gravity due to it's spinning?
@Saravanan: 1) You are courageous to try to write this much English when it is not your first language. 2) Still, I am having difficulty understanding your intuition. I understand a person doing a vertical jump and landing in the same place relative to a moving earth. You seem to see a difficulty with this, and I do not.
Aug
4
comment Does Earth get gravity due to it's spinning?
Suppose you are traveling on a bus at 30 mph, and you are standing up. Now you jump straight up. Where do you land? The man on the grass is also on a bus, that is traveling 1000 mph to the east. In fact he is traveling 70,000 mph to get around the sun in 1 year. In fact he is traveling 5 times that around the center of the galaxy. Who knows how fast the galaxy is traveling, relative to others?
Aug
2
comment What really allows airplanes to fly?
For stability, "god fearing" aircraft have the center of gravity forward of the center of lift of the main wing, and the tail plane counteracts this by lifting downward. This means as the plane slows down, there is less downward force at the tail, so the nose drops, increasing the speed. Fighter planes are designed to be unstable - a computer keeps them balanced - so they can roll, pitch, and yaw very rapidly.