8,542 reputation
1730
bio website en.wikipedia.org/wiki/…
location United States
age 71
visits member for 3 years, 9 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 Can a photon have little to no energy and/or speed?
@Daniel: You're absolutely right. I'm trying to keep it simple for an OP who is clearly a newbie to physics.
4h
answered Can a photon have little to no energy and/or speed?
4h
comment Can a photon have little to no energy and/or speed?
Its energy is a function of its frequency (color) not of its speed.
4h
comment Can a photon have little to no energy and/or speed?
When photons go through a material, like glass or water, they travel more slowly. There are materials in which they can go very slowly. But that does not reduce their energy.
Jun
26
answered Why do the tangent holes (like in pitot-static tube) feel the static pressure?
Jun
26
comment Simple Beam Worst Case Scenario
You can figure it out. Hint: Try moving F all the way over to P1 or P2.
Jun
24
answered Water pressure on a floodlight in a swimming pool
Jun
24
comment Why Owl wins and aircraft loses in the competition of silence?
Owls are very quiet gliders, having specialized feathers. The quietness is partly because their gliding speed is quite slow in absolute terms, like 50 km/h. If someone wanted to build an aircraft that could glide very slowly and quietly, chances are it could be done.
Jun
24
comment From Civil Engineering undergrad to Physics grad
I'm afraid you're not going to get a satisfactory answer. I had undergrad in Mechanical Engineering and Master's without designation, having done the work in M.E. and Civil Eng. I wanted to get a PhD in Computer Science, specializing in Artificial Intelligence. I eventually did that, but not from a top-tier school, although I was able to do the research at a top-tier school. The difficulty was I did not have the coursework considered standard. So from my viewpoint, it can be done, but you are the only one who can figure out how.
Jun
24
comment Direction of pressure forces on a control volume (surface)
@FredikLAa: To help you understand, 1) assume the velocity is 0, and 2) assume the volume is a cylinder with a piston on the right. The fluid is pushing out, and to keep it in place, the piston is pushing in. Then, convince yourself the velocity doesn't matter - i.e. there can be leakage in the left and out the right, and it doesn't change anything.
Jun
23
answered Direction of pressure forces on a control volume (surface)
Jun
23
comment Why wasn't the moon visible during the day a few decades ago?
@Kyle: You need to see it when the moon is in a phase such that there's a good bit of it to see, and that determines the angle at the viewer between the moon and the sun. At half-moon, for example, the angle is $90^0$, so if the moon is high in the sky, the sun is low. On the other hand, if the moon is full, the angle is $180^0$, so you can't really see both at the same time (if there are any obstructions around you like trees or buildings).
Jun
20
comment Is it possible to make a low dense object sink in a fluid of higher density by cutting the object in particular shapes?
Aren't you just describing a suction cup?
Jun
19
comment Drift of Earth's orbit?
+ ... "Wagnerian doom" :)
Jun
19
comment Could one fire a bullet with sufficient speed to leave the Earth?
Sure it's possible. All you have to do is have a gun barrel tall enough reach above most of the atmosphere, and fill it with near-vacuum. Another way: make sure your bullet is skinny and tall, to reach above most of the atmosphere. Either way, you use a big-enough propellant and a long-enough barrel.
Jun
19
answered Physics of the inverted bottle dispenser
Jun
19
comment Why does voltage change in series circuit but not in parallel circuit?
I was going to give an answer using intuition about water pipes with half-open valves, but this answer is just as good if not better.
Jun
17
comment What is the best way to calculate speeds at other points in a venturi-tube when knowing one?
Now that you edited the question, $1.8*(10/13)^2 = 1.06$ should be the velocity at point 2, based on volumetric flow rate.
Jun
16
comment What is the best way to calculate speeds at other points in a venturi-tube when knowing one?
@Ruben23630: Your diagram says the areas are getting smaller, but your numbers say they are getting bigger. Could that be the problem?
Jun
15
comment Electrolysis boat engine
I'm not so willing to dismiss this idea. It is basically a way to do electric propulsion, by turning electrical energy into heat. The ignition can be done one way or another. I'm not saying this is a good idea, but neither would I reject it out of hand.