Recent content by pop_ianosd

I am tutoring a student on 7th grade math via zoom. I am using graphics tablet myself to write down my exposition. My student solves problems on his (paper) notebook and tells me what he wrote/how he thought it out and I re-write it on the screen and make eventual corrections. I have the...

That is what I understand to be happening as well. It must be the case since, as mentioned in the original question, there is an outward electromagnetic force. Half the energy provided by the external power source gets stored in the magnetic field, and half goes into mechanical work. Your...

Ah, now I get your point. Yes, it makes sense now, thank you!

Sorry, I had the wrong picture in mind, and the statement that energy must be fed into some other place is misleading. What I see is happening if you increase the loop while somehow maintaining constant current is, indeed, as you are saying, that you have an increase in the field-stored energy...

The energy stored in a current loop equals ##\frac{LI^2}{2}##. From a dimensional argument, it follows that the inductance grows with the size of the loop. This would mean that, if we assume the current stays constant, enlarging the loop would require external positive work, so, the force...

I'm confused by problem 1. What's the difference between f_0 and f_1?

Thank you for the answers! The image of the convex effective potential gives a nice intuitive reason for why the condition is sufficient for stability. I'm not sure I understand what you mean by Is this meant to be an argument for why the orbit is stable? Because if that's the case my problem...

In this chapter, the stability of an object orbiting in a circular orbit of radius r_c in an arbitrary force field f is considered. The author arrives at the equation of a harmonic oscillator, for small deviations x from the circular orbit: \ddot{x} + \left[-3\frac{f(r_c)}{r_c} -...

How? I see how it is used whith homogenous materials, but how can it be applied for a discontinuity? I may be missing something.

Consider the interface between two materials with different electrical permitivities ε1 and ε2; Let's say we know the surface charge density on this surface γ(Let's say the only charge is on the interface). How do you apply Gauss's Law here. Or, How do you find the elecrtic field at a random...

So here is my current state: I am int the 12th class (that is senior), in Romania. My connection with physics is good, certified by me participating at national physics contests, having some notable results(of course, this is not an absolute argument).So I thought about aiming for a career in...

Homework Statement A given pozitron with T kinetic energy is approaching an electron bound to a hard nucleus(in the K energy level, and the ionization energy for this level, Ek(>0), is given). The energy of the two resulting photons is to be determined.Homework Equations Conservation of energy...