8,542 reputation
1730
bio website en.wikipedia.org/wiki/…
location United States
age 71
visits member for 3 years, 9 months
seen 9 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.


Jun
15
comment Reduced gravity flight's affect on convection based cooling
I think your suspicions are right on both counts, although if there is a fan (as in this laptop) the convection issue would not arise. Whether the effect is significant, I don't know.
Jun
15
revised Why is a beam reach the fastest point of sail on modern sailboats?
spelling
Jun
13
comment By what factor would you have to slow down time for water to feel like glass?
The idea that glass is a liquid is an urban legend.
Jun
13
revised Can lift contradict conservation of energy?
added 393 characters in body
Jun
13
answered Can lift contradict conservation of energy?
Jun
13
revised Why is a beam reach the fastest point of sail on modern sailboats?
added 136 characters in body
Jun
12
revised Why is a beam reach the fastest point of sail on modern sailboats?
added 85 characters in body
Jun
12
comment Fluid Dynamics applied to Aircraft wings
Please check out the other answers on the site. The flat-bottom-curved-top business is a widely-taught absolutely wrong explanation, and totally fails to explain aerobatic airplanes, which have symmetric airfoils. They fly just as well upside-down as right-side up. Almost any shape can fly, as long as it pulls the air into a downwash.
Jun
11
comment If one object, moving at a constant speed collides with another object - which is at rest - how much force has been applied?
There is no answer, because it depends on how stiff they are. If they are tennis balls (springy) the force will be less than if they are steel (hard).
Jun
1
revised Why is a beam reach the fastest point of sail on modern sailboats?
deleted 6 characters in body
May
29
revised Why is a beam reach the fastest point of sail on modern sailboats?
added 377 characters in body
May
29
revised Why is a beam reach the fastest point of sail on modern sailboats?
added 11 characters in body
May
29
answered Why is a beam reach the fastest point of sail on modern sailboats?
May
28
comment Why is a beam reach the fastest point of sail on modern sailboats?
Have you ever taken a wet watermelon seed between your thumb and finger and squeezed it, to make it shoot out? That's a crude way to describe what's going on. The sail is one finger, and the centerboard is the other. If there were no water drag, there is really no limit to how fast the boat could go. It can really do this downwind or upwind as well, but the effect is strongest on a reach.
May
28
comment Coriolis Effect vs airplane
@pittacus: If instead of an airplane, you launched a rocket above the atmosphere, yes it would be in a different place when it reached the equator. In the airplane, the air mass it is traveling in gradually picks up speed as the plane goes south, so it would experience this as a slight force from the right, just as in the car. Any plane is constantly adjusting for wind, so it would not be noticed.
May
26
comment How do compressible fluids behave near a sink?
You have a spherical reservoir, in 0G, with a sink at the center. Velocity depends on the volume flow rate out of the sink, and you don't say anything about that. As long as the velocity is sufficiently below the speed of sound in the fluid, you can treat the fluid as incompressible. Keep in mind you're going to get a vortex around the sink, because the angular momentum of the fluid will almost certainly be > 0.
May
26
answered Are atoms compressible?
May
24
comment Balloon aerodynamics
You're basically saying the balloon is a bubble, and as it goes up, it expands (just as it would if it only contained air, not helium). That doesn't explain the extra tube hanging off the gas bag. I don't know its purpose either, though I can guess it's for filling, as @PeterKämpf said.
May
22
revised Determine travel for different rate springs in series
edited body
May
22
answered Determine travel for different rate springs in series