8,810 reputation
1730
bio website en.wikipedia.org/wiki/…
location United States
age 71
visits member for 3 years, 11 months
seen 11 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
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
revised What are the proper unit types for the calculation of the frequency of a tuning fork?
math formatting
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.
Aug
2
comment What really allows airplanes to fly?
@Pacerier: No way. When a wing is stalled, then it is like a parachute, and not a very good one. Stalling, which means increasing the angle of attack so the airflow becomes detached, is a good way to descend much faster than you probably want to.
Aug
2
comment How a paper plane(rocket) flies in air? what is science behind it?
I really don't like to downvote, but I would encourage you to learn something about the subject. Aviation and rocketry have been around for a century, so there is a lot you can learn from those who know.
Aug
2
comment Is wave-particle duality not clear from the single-slit experiment?
I agree with your last paragraph, except the pattern would not be gaussian. Essentially the slit would act as a line source of radiation.
Aug
2
comment Is wave-particle duality not clear from the single-slit experiment?
You're right, but I think it is best to think of an ideal slit, not a messy one with particles at the edges. With an ideal slit you get the interference pattern, and the more narrow the slit is, the wider the pattern.
Aug
2
revised Is wave-particle duality not clear from the single-slit experiment?
deleted 2 characters in body
Aug
2
comment How a paper plane(rocket) flies in air? what is science behind it?
You don't realize it as you walk around or maybe run, but if you're in a car at high speed and you put your hand in the wind, air is heavy stuff. I encourage you to learn about how things fly in it, and here's an excellent place to start.
Jul
31
comment Why does an image form at the intersection of light rays?
@user132522: Don't call your English bad. It's far better than my Spanish, and that's far better than my French, German, Portugues, Greek, Korean, etc. We hosted students learning English. A Brazilian woman wanted to speak English with no accent. I told her no - your accent is charming. Keep it.
Jul
31
comment Why does an image form at the intersection of light rays?
@user132522: I guess English is difficult. Yes "right side up" means "upright. The lens of your eye forms an image on your retina. The image is "upside down" or "inverted", meaning the sky is in the lower part of the retina, and your shoes are in the upper part. Left-right is also swapped. But your optic nerves twist it so it looks upright.
Jul
31
comment Why does an image form at the intersection of light rays?
@user132522: I'm not sure what you're asking.When a light ray strikes an interface plane between two transparent media having different indices of refraction, the light beam will change direction, and if the angle is shallow enough, it will reflect off the interface plane, just like off a mirror. You can easily see this in a table-top aquarium filled with water.
Jul
31
revised Why does an image form at the intersection of light rays?
added 49 characters in body
Jul
31
answered Why does an image form at the intersection of light rays?
Jul
28
comment What stops giant cruise ships toppling over in rough seas?
@Acid: Every such boat is designed by engineers and you can be absolutely sure they've thought of that. You can be sure they have written a user's manual saying things like: putting more weight than XXX on decks YYY will "void the warranty". They know what they're doing.
Jul
28
comment What stops giant cruise ships toppling over in rough seas?
They look top-heavy, but they are not. Suppose you took a row-boat, and put a few hundred pounds of cement bags in it. Then pile cardboard boxes on top several feet high. Same idea. It might look top-heavy, but if you try to push it over, the weight in the bottom will bring it back up.
Jul
27
comment What's the max speed a man-made satellite can travel in space before its circuitry stopped working?
Nice, but I would have said something like 1 - 2e-14 or 1 - 2e-7, rather than string a bunch of 9s and make me count them :)
Jul
26
comment Breaking the sound barrier underwater
Google supersonic torpedoes.