Thanks for the replies guys, and those links are really helpful. I managed to find NEMA documents for "overclock"ing AC induction motor.
The current low rpm is just due to motor and material constraint, at this stage we just want to test if our magnetic bearing works (low energy lost for a...
A lot of the parameters are not fixed yet, the only thing we're sure about it is its going to be low budget.
Yes, magnetic bearing is needed.
Another option I'm thinking is put the motor outside, then use magnetic coupling to drive the rotor, once the flywheel is spun up, we pull the...
Hi
Me and my friend is starting a project to building a flywheel system with aim for energy storage. This is a small budget experiment to see how long flywheel can hold energy with our design. One problem we face is finding a suitable motor, we plan to use induction motor to avoid eddy...
Good explanation, though momentum uncertainty is infinite, its average value is indeed zero. If we can observe at extreme resolution we might find the particle doing random walk under repetitive measurement, for what little time wavefunction gets to evolve.
I kind of understand the question OP asked and I'm puzzled too.
If I understand it right, q zeno effect means when you measure the state of a system, wave function collapse into one of the eigenstate, and if you repeat the measurement fast enough you'll get the same state because the...
I've been looking at nonlinear control system and fuzzy control in particular.
If I simply want to do trajectory control (have the system to follow a certain trajectory in phase space), can I use much simpler local linear control?
I mean, for each point in phase space, do a local...
Lets consider this in detail:
consider a photon moving back and forth, it will impart equal (but opposite sign) momentum when reflected by both sides.
consider the case when a photon is moving towards -x direction after the box is accelerated, photon is blue shifted, thus when it hit the...
Again, the analogy of a box with bouncing balls holds very well. If the mass of the box is very small, then indeed when force is applied you get a very large acceleration (lets not deal with infinities). Until one of the ball hits the box and transferred momentum and bounced the box back and...
That's exactly the calculation I did. As to what supplies the inertial force "before", you can think of this box simply as a box holding a bunch of bouncing balls inside. Before any of the balls hit the wall you won't have any reaction force too.
Actually I've done a similar thought experiment and found out the box of photons does have an inertia exactly equal to the mass of the photons combined (ignoring the mass of box). But it is not due to gravity, it is due to radiation pressure of photons.
Suppose you push the box, result in some...
Just read Feynmen's QFT and been wondering the difference between photon reflection by a perfect mirror and photon scatter by say a rough surface.
In both cases, photons are said to be absorbed by electrons and re-emitted.
But in reflection case, photons get to "preserve" its wave...
Hot plasma have pressure, if it's just a ordinary blob of hot gas then it obviously will expand. But there remains a remote possibility that the plasma having an internal current inducing B field to somehow contain itself (scifi plasma bolt anyone?). Radiation lost and thermodynamic lost...
I was looking for the Virial Theorem, my motivation is along the line of why can't a hot plasma of any possible configuration confine itself by EM interaction between the particles alone. I think Virial Theorem answer that, but as Vanadium 50 point out: how about a pair of proton and electron? I...
Yes, you are right. There must be some kind of assumption in the theorem, care to figure it out?
http://en.wikipedia.org/wiki/Virial_theorem
It's a general theory that deal with any force interaction, EM interaction takes special treatment.