Recent content by EFuzzy

Firstly, the net horizontal force on the dielectric is going to be zero, since there are TWO forces pulling the dielectric to the side, one on each side of the dielectric. The reason the dielectric is pulled inward is due to the fringing field of the capacitor, the part of the field that is...

OK, thanks a lot! I'm kind of disappointed actually, because the book seemed to contain some interesting problems, but it's not really worth it if some of the solutions are wrong.

While searching for a collection of interesting mechanics problems, I stumbled across this set of problems. http://www.mechanics-book.net/mechanics_problems.pdf Problem 57 and the given solution are attached. However, I think there is an error in the solution. They assume that velocity of the...

Thanks!

Thanks for the link, this is a problem I've been annoyed with for a while too. I've worked out a semi-proof for the 2d case using similar triangles, but I would like to see the 3d case as well. Do you have a link for a free copy of the paper?

I guess the problem is that I don't fully understand how the internal resistance works. The voltage difference from one plate to the other is going to be vBd, so why does it matter what's going on between the plates? All the resistor will notice is that the capacitor provides some constant voltage.

There was an interesting problem that appeared in POPTOR 2005: A generator consists of a parallel-plate capacitor immersed in a stream of conductive liquid with conductivity \sigma. The surface area of a capacitor's plate is S, the distance between the plates is d. A liquid flows with constant...

U_2-U_1=C_v(T_2-T_1) ALWAYS holds for an ideal gas because internal energy is only dependent on temperature, and not on pressure or volume etc. I'm not sure what H_2-H_1 means in the second equation. W=R_0 x T x ln(P' / P) can be obtained by integrating P*dv and using PV=nRT.

A cube has 5 sides grounded, and an insulated sixth side at potential x. What is the potential at the center of the cube? The solution states that the potential at the center must be a linear combination of the potentials of the six sides. Why is that? Thanks, EFuzzy

Oh thanks, that explains it. So if the axle was pointed straight up instead of at an angle, would the caster disappear?

Hello Everyone, My friend and I were having a discussion of why car wheels would naturally return back to a forward position if one doesn't hold on to the steering wheel. It could be that its just the car turning to match the direction of the wheel, but I think the wheels turn more to match...

The book agrees with durt. Thanks for the explanation!

Thank you all for your responses! I've got a good idea now of how the problem works now. I think what's happening with the "non-traditional" force is that force is best defined as dp/dt, with f=ma only applying when mass is constant. Thus force can maybe either increase mass or increase speed.

Brightness, in that problem, probably corresponds to the power output of the lightbulbs. Remember that power = current * voltage drop

Oh, OK, I see what you were trying to say then. Is there any time we would want to use the dm/dt *v + m *dv/dt expansion then? Because the only way mass could change is if objects combined or broke up.