8,667 reputation
1730
bio website en.wikipedia.org/wiki/…
location United States
age 71
visits member for 3 years, 10 months
seen 4 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.


4h
comment Why will a 'Non-Electric Faraday Motor' which just uses permanent-magnets, not work?
You can edit your original question if you want to clarify it or add an image.
1d
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.
1d
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.
1d
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.
1d
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.
1d
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.
1d
revised Is wave-particle duality not clear from the single-slit experiment?
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1d
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?
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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 Why is not the entropy of earth increasing?
@Acid: I disagree with your last paragraph. The second law applies to closed systems, which the earth is not.
Jul
27
comment Why is not the entropy of earth increasing?
@pentane: Entropy can be defined as the integral of $dQ/T$, so it's not unreasonable to say sunlight at high temperature is energy at low entropy, and radiational cooling is the opposite. No?
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.
Jul
23
comment Finding minimum time to raise a bucket
It's good that you tried to solve it yourself and showed your approach.