วีดีโอ

Muito bom.

Awesome thank you!

concurs with the work i've done so far! Just unsure how i could simulate the equations since they're implicit ):

absolutely beautiful work!! i hope this blows up as more people work on projects like these.

Thanks professor.

thanks it is very helpful

THANK YOU SO MUCH :)

Thank you very much for the detailed solution!

I really enjoyed this exercise! You clearly showed that energy is not conserved when potential energy changes over time. This is very important, though rarely observed. Conservation of energy is not a universal law, but only applies when potentials are conservative.

We can see that E is dimensionless. But angular momentum has dimensions as [L]. But E and L are defined as two constants of motion. Why is L not dimensionless? P.S please reply tomorrow is my defense 😢

Hello sir, Relativity offers explanations for the magnetic force between a moving charge and a wire with current, attributing it to concepts like length contraction and charge density variations. I recently encountered an explanation regarding a real case scenario where a wire contains both electrons and protons. However, my question pertains to a hypothetical scenario: How does relativity explain the generation of a magnetic field in an infinitely long wire uniformly composed of either positive or negative charges? Specifically, when a charge moves perpendicular to this uniform charge distribution, the Lorentz force law predicts a horizontal magnetic force. How does relativity account for this horizontal magnetic force in the absence of traditional current flow? Could you elaborate on the theoretical framework that relativity provides to understand these magnetic effects in a wire with uniform charge distribution, particularly addressing the role of length contraction and charge density variations in this context?

My god man, you've got to write bigger!

Would frame dragging explain this paradox?

Thank you You should be more famous

Thank you!

The video was really helpful but can you check the partial differentiation of the x1, looks like there was a mistake with the sign used ... plus instead of minus

😢😢😢

never give

💪 *Promosm*

super duper helpful, thank you

Hello! Could you derive why the Lagrangian has to be kinetic minus potential energy? Like if you were discovering it for the first time

Thank you very helpful

where does the equation at 1:20 come from?

Nice video. On the Wikipedia page, it was mentioned that ehrenfest had shown that the circumference is smaller while einstein argued like you have showing that it is larger. Both show that the spacetime for the disk is non euclidean so, which one is correct?

very helpful, thank you

Promo SM ☹️

10^10^36 SOLAR MASSES OF MATTERS

thanks for this

Literally my favorite topic. It always gave me a headache how the notation changes from field to field (MCAT, physics books, chemistry books). Anyhow, Carnot would be happy to see you educating others on this. Cheers

White hole

A VOID SWALLOW OBSERVABLE UNIVERSE

Your channel needs more exposure! Great stuff

Hey there David, you seem like a very intelligent man who may be able to answer my question. Are you aware of any sort of energy that contains itself, without needing to be grounded to something. Without a heavy dense gravity to hold it in place. Just free floating energy that is self-contained and doesn't come apart without a physical conduit so to speak. I hope you understand what I'm saying I'm probably not saying it right according to pie intellectual concepts but, an energy that doesn't disperse without something holding it together. Like gravity is holding the sun together right? Electricity travels down a wire, even humans we produce energy but it's in our bodies. Is there any sort of energy that you're aware of that can just exist without a physical conduit and not disperse? Thanks man.

Thank you so much for this video. Your lecture is very rich. I'm convinced now that work done by magnetic force on a single charged particle is zero.

great video, thank you!

☺️ Promo>SM.

You did not get the proper and fundamental physical difference: "average" squared velocity (v2). You can calculate it from whatever inertial frame you want; the "average" squared velocity (v2) of the traveling twin is always higher. I think this is the fundamental physical difference.

In my opinion, solving the TWIN PARADOX means solving a system of two equations with four unknowns. I consider the two Lorentz transformations: a) x_1 = gamma * (x -v * t) b) x = gamma * (x_1 + v * t_1) With gamma I obviously indicated the Lorentz factor, and I do not consider the other two Lorentz transformations because they depend on a) and b). In an empty space THE TWIN PARADOX is not resolvable, it’s impossible to determine a single solution of a system of two equations with four unknowns. BUT THE TWIN PARADOX “IS NOT A PARADOX”, if you consider the astronaut twin moving with speed v to reach a star. The Earth and the star both belong to the frame of the Earth, and we assume that the Earth-star distance is equal to d in the frame of the Earth. F: Alice's frame (frame of the Earth) F_1: Bob's frame (frame of the spaceship) We know that Bob's spaceship moves in the frame of the Earth with uniform rectilinear motion at speed v. (x = v * t) Let’s consider again the system of two equations: a) x_1 = gamma * (x - v * t) b) x = gamma * (x_1 + v * t_1) If x = v * t (x_1 = 0), then t_1 < t. (v * t = gamma * v * t_1, t_1 = t / gamma) If (x = v * t) and (x_1 = -v * t_1), we obtain “the useless solution”: x = x_1 = t = t_1 = 0. I indicate (x_1 = 0, x = v * t) with (c) , and I indicate (x = 0, x_1 = - v * t_1) with (d). (c) and (d) are MUTUALLY EXCLUSIVE! If it is true (c), it is not true (d). If it is true (d), it is not true (c). If x = v * t, then t_1 < t. (spaceship clock slows down compared to Earth clock) If x = v * t, it is not only the Earth that moves with velocity -v, it is the entire Earth-star distance that moves with velocity -v. The spaceship actually moves with uniform rectilinear motion between any two points of the Earth’s frame (if the acceleration of the spaceship is zero), we cannot choose x_1 = - v * t_1. (the choice x = v * t it’s obligatory)

In my opinion it is impossible, even if the pole moves at speed close to the speed of light. If two equal distances are in relative motion to each other at speed v, the distances overlap. In my opinion, if we denote with t the elapsed time in the frame of the barn and if we denote with t_1 the elapsed time in the frame of the pole, it is t = t_1. (and two equal distances overlap, in this case no problem) The length of the pole contracts in the barn frame and the length of the barn contracts in the frame of the pole, the two lengths are equal! (suppose they are equal to d) d = gamma * v * t and d = gamma * v * t_1. When the two distances overlap it is t = t_1 = d / (gamma * v), for each value of d. If the length of the barn is shorter, in my opinion it is impossible! If an athlete runs at speed v without the pole, then the situation is different. (there are no two distances in relative motion between them) In this case x = v * t and t_1 < t. (the athlete's clock slows down compared to the barn clock)