Recent content by stevenb

A couple of decades ago, I worked out a derivation of Biot Savart's law based on Coulomb's law, and relativistic length contraction. This is analogous to how you can derive the force between two current carrying wires as being due to the different reference frames for the moving and stationary...

I am reasonably familiar with the typical electrical and mechanical engineering curricula, but I'm less familiar with the mechatronics curriculum. Without knowing the details of mechatronics coursework, I would also have a similar concern as you. My worry is that by not covering the full...

I don't know if this will help you at all, but remember that voltage is relative. When you say the potential is zero, it is zero relative to your ground. This is analogous to gravitational potential energy. If you say that potential energy is zero at the surface of the earth, it it relative and...

It's not clear to me what you are doing, but a diagram might help. My best guess is that the resistance is 4.45V divided by 0.93 mA which is 4785 Ohms. But without an understanding of what you are doing, that caculcation might not be the right one, or the experimental method could be...

What is your model for the plant (thermal system) you are trying to control? The closed loop response is a combination of the controller transfer function and the plant transfer function. So, you can't predict stability or optimim PID gains without consideration of your plant. If you don't know...

I don't know how phyics can help here. Cats are unpredictable. 1. We lost our cat named zero years ago. After two years we found it was living at another house two blocks away. 2. Our neice's cat jumped in the neighbors car and ended up at a grocery store 8 miles away. The neighbor saw the...

I agree that Newton did not express or contemplate about a number for G. His careful experimental verifications involved various data about Jupiter's moons, Saturn's moons, the Earth-Moon system and the planetary orbits around the sun. He did not need the exact values of the masses of the bodies...

HallsOfIvy, I think you just squared each term, rather than squaring the whole expression?

Well, batteries are not quite storing charge, but is a chemically based electromotive force. But, if we think of a capacitor, we can think of real charges stored on plates, and get to the same question. So, if you don't create a closed circuit, by using yet another wire on the other two...

There can be (and is) a potential difference between those terminals. The issue is measuring it. Any voltmeter has a finite source resistance built in. Although large, it is typically comparable to the resistance between the open terminals. So, any measurement will either appear to drift, or may...

It's hard for me to say. I think we need someone knowledgeable about physiology of the muscles to answer that. From a physics point of view, gravity is doing work when we lower the weight, and the person is just restricting the rate of work done (power). But, obviously we know we burn calories...

There is a difference between physical work done and actual calories burned. The question is clearly asking you to ignore all efficiency effects Additional calories are burned for stabilization, returning the weight to the start position and even rebuilding muscles and recovery processes later...

Complex variables are critical for electrical engineering, not just beneficial. I like "Complex Variables and the Laplace Transform for Engineers" by Wilbur R. LePage. The Dover edition is not very expensive. It's not an introductory book, but it will serve well in the long term and requires...

Well, yes, of course. The OP mentioned "invertibility" of the linear system, which I think amounts to the same thing. And, there are other ways to check it too. This is one point I was trying to make; that, as a practical matter, we can check it on a case by case basis as needed. However, if the...

Well, above you see the practical concerns, but I was thinking more about the mathematics. Just write out the equations to see it. V1=V2 Kirchhoff's Voltage Law V1=10V Ideal voltage law for battery # 1 V2=20V Ideal voltage law for battery # 2 So, two batteries in parallel can't obey...