Rick16's latest activity

I just thought about something. I am new to Landau and I am not familiar with his style. When he writes the displacement as ##dl_1^2...

This problem has been addressed before under...

In any case, this is my first reading of the text, and I am satisfied that I can show that ##\vec v## is constant when I assume that the...

@Vincf already had a counter example in #5.

The fact that dL/dv is constant was never the question. The question was why v is constant.

This would be my next problem: I don't understand the paragraph before equation 4.1. But like I already wrote, my head is already...

I also tried out several different functions for ##L(v^2)##, but I found that the velocity was constant for all of them. You apparently...

Yes, I know, but PeroK's suggestion is one way to see why the velocity would have to be constant (provided I already know the form of...

I just wanted to ask why on earth the Lagrangian would be ##L=\sqrt {v_x^2 +v_y^2 +v_z^2}##, when I discovered that you had changed...

Thank you, that is an interesting trick with the ratios. It is not likely that I would have thought of it. I suppose you know how to do...

This question does not seem to evoke a lot of interest. Could somebody just tell me if it is legitimate to write ##\frac{d}{d\vec...

I have begun reading Landau's Mechanics. In chapter 1, §3 he writes ##\frac {\partial L} {\partial \vec v}=const.##, where ##L## is a...

Thank you. This is it. It is not even new to me. I read about it probably more than once, but I had completely forgotten about it. This...

One more comment to show where exactly my problem lies: Potential energy is defined at a specific position. A System does not have a...

Here is the solution: The kinetic and potential energies of the system are $$U_k=2\cdot\frac{1}{2}mv^2=mv^2,~~~U_p=-\frac{Gm^2}{2r}.$$...