6,491 reputation
928
bio website embedinc.com/olin
location Littleton, Massachusetts
age 58
visits member for 1 year, 7 months
seen 22 hours ago

Electrical engineering consultant specializing in microcontrollers and the circuitry around them. Master of engineering in EE from Rensselaer Polytechnic Institute in 1980.

We are certified Microchip design partners, and have been in the top catagory consistantly since around 2000. Various free downloads related to developing PIC firmware and other things are available at http://www.embedinc.com/pic/dload.htm.


Sep
16
comment If the universe is expanding, what is it expanding into?
1: Into more universe. 2: Everywhere. 3: Nobody knows. 4: Nobody knows.
Sep
14
comment How to calculate when wheels are better than legs?
First, your "question" contains several assumptions that you haven't proven and I'm not at all sure are correct. This therefore can't be answered in its current form. Second, this is a biomechanics problem.
Sep
11
comment Is this scene from the A Team explainable by Physics?
@Aron: As I said in my answer, even if I was off by a order of magnitude, the result would still be the same. You link shows that muzzle velocity is almost 1800 m/s, but shell mass a bit lower than the 10 kg I used and the M1A1 tank a bit heavier than the 50 tons I used. All in all it seems I was low by a factor of 5. 0.8 miles/h speed change still isn't going to matter.
Sep
10
comment Is this scene from the A Team explainable by Physics?
Very little from The A Team is explainable by physics.
Sep
8
comment Where does the extra kinetic energy come from in a gravitational slingshot?
The energy comes from the kinetic energy of the planet going around the sun. The orbital speed of the planet is slowed down very slightly as the spacecraft passes by.
Sep
7
comment Formula for Electrical Arc Length
You look up the breakdown voltage of whatever material (like air) you want to arc thru. Then multiply that by the distance between electrodes and that's the voltage you need.
Sep
5
comment Why is it hard to make black clothes?
What material do you know that absorbes absolutely all visible light, reflecting nothing at all. "Nothing" is a rather small value. The same issue goes for white too. Some material would have to reflect all visible light.
Sep
5
comment What really happens atomically in an explosion?
The cigarette heats up a few oxygen and butane molecules, which causes them to combine, which releases heat, which heats up even more oxygen and butane molecules, etc, etc, boom.
Sep
4
comment How is voltage increased from a battery?
@Floris: My answer is "voltage wasn't increased", so of course I can't talk about how it was increased, since it wasn't.
Sep
4
comment How is voltage increased from a battery?
Whoever downvoted this: What exactly do you think is incorrect, misleading, or badly written? I have re-read what I wrote and still believe it to be correct.
Sep
4
comment How is voltage increased from a battery?
Yes, it is possible to convert from a few 10s of volts to 30 kV, but this makes absolutely no sense for a copter. The converter would take space, weight, and waste power. And then the extra handling required for 30 kV would force more weight and space wasting. And then there are safety concerns. I don't know what the OP really saw, but it wasn't a small copter running its motors from 30 kV. No way.
Sep
4
comment How is voltage increased from a battery?
@Alan: That 1 kV brushless motor won't be intended for battery operation. It is probably a large and high power motor so that the reduced current required at high voltage becomes a benefit.
Sep
3
comment The best way in which a man can pull a train
@bobie: I don't consider the question stupid. The problem is that you don't really understand forces and energy. This is context necessary for understanding answers to your question. That is something this site is not well suited to deal with. You seem to be wanting to understand, so I really think reading a introductory physics text would be a good move for you.
Sep
3
comment The best way in which a man can pull a train
@Señor: Then perhaps you can try explaining this to someone that doesn't really understand forces and energy. It's OK to ask basic physics questions here, but asking more complicated ones when you don't understand the basics enough to make sense of the answer just doesn't work well for this site. What would you have me do, duplicate the introduction of forces from high school physics? That would be long, and no different from what the many existing text books already do, hence the recommendation to go read one.
Sep
2
comment Will I be able to push a small object in front of me in the outer space?
When you push the back end of a spaceship from inside, you are making it go bacwards slightly, but you also forwards a lot faster (since your mass is a lot less than the spaceship's). Eventually you will hit the opposite wall in the spaceship. That pushes it in the opposite direction, cancelling the push you gave it earlier.
Sep
2
comment The best way in which a man can pull a train
@bobie: In the lateral direction it is. All forces have to balance (when there is no accelleration) along all directions. Breaking this up into vertical and horizontal is useful because the pulling force is horizontal and gravity is vertical.
Sep
2
comment The best way in which a man can pull a train
You asked about forces, and now you're confusing things by asking about energy. Sorry, but it seems you don't really understand either, and this isn't the place to replay a year of high school physics before answering a question. Go read a basic introductory physics text.
Aug
29
comment Who does work while walking?
@Ben: Yes the ground doesn't do any work. However, the muscles do work to push that center of mass against gravity. If this weren't true, you'd be doing no work by standing up on tiptoes starting with feet flatly on the ground. You'd be doing no work going up stairs either, since the steps are only providing a force. Your concept doesn't work.
Aug
28
comment Can I throw a stone through my window without breaking the glass?
@Roger: No, to a confidence level of 0. followed by a lot of 9s. Something the mass of a "tiny stone" tunneling thru something the thickness of even the thinnest plausible window glass is so astronomically small as to be impossible with a certainty well beyond plenty of other things we consider "certain" without question. So basically "no".
Aug
27
comment Why does frequency increase as the length of an open air column shortens?
Basically shorter wavelengths make higher frequencies. How is this not obvious?