Recent content by wnvl2

On a Dutch forum, there is a discussion about the following problem: A ##1 \mathrm{kg}## mass slides across a frictionless floor with an initial velocity of ##10\, \mathrm{m/s}##. The top surface of the mass has an area of ##1\, \mathrm{m^2} ##. The floor is perpendicularly irradiated with...

Assume the radiation is uniform in the emitter's frame. In that case, there is no acceleration in that frame. However, from the perspective of the ground, the radiation is not uniform. How can you explain that there is no acceleration in the ground frame?

HansH’s question is inspired by the following scenario: A cannonball is fired from reference frame 1 (the cannon). After a brief acceleration, it continues to move at a constant velocity relative to reference frame 1. Reference frame 2 is the frame moving along with the cannonball. Due to the...

A 1 kg mass slides over a frictionless floor at a speed of 10 m/s. The mass has a top surface area of 1 m². The floor is uniformly irradiated with an intensity of 1 W/m², and the radiation is perpendicular to the floor in the floor’s rest frame. All incident radiation is absorbed by the...

Do you mean that in most cases of lensing, the metric is not stationary, which results in the shifts generally not being the same? Otherwise, if the metric is stationary, wouldn’t that contradict what Ibix writes?

Can gravitational lensing serve as an example of a phenomenon where multiple paths are possible? How can I know in such a case that the frequencies from both paths will be the same?

I read most of Schutz and I know the lecture notes from Carroll. It is not that my understanding of general relativity is just based on chatgtp. I want to leave the spacetime geometry open. Limitations are that there is no cosmological constant and that the metric is stationary. The question...

Is the redshift of a photon between two events independent of the path? I assume for this question that the the cosmological constant is zero. Chatgpt writes: "In a gravitational field, the redshift can depend on the path taken by the photon. For example, in a Schwarzschild metric (which...

I think I understand it now better. I haven a system with 2 degrees of freedom ##\phi## en ##\theta##. The equations of motion are $$\frac{d}{dt}\frac{\delta L}{\delta \dot{\phi}}-\frac{\delta L}{\delta \phi} = -mg(a \sin \phi+l\sin\theta)$$ $$\frac{d}{dt}\frac{\delta L}{\delta...

I want to calculate the equation of motion of a planar pendulum of length l with a mass m at its end and a pivot point that moves uniformly along a vertical circular path (radius a) with a constant frequency ω. The Lagrangian and the equation of motion for a planar pendulum with a moving pivot...

I was a little bit in doubt after the reply from Gandalf on this topic here on stackexchange. Question was: "Since tensors are invariant under coordinate transformations, and a moving observer is just in another coordinate system, he should measure the same Riemann curvature tensor (with...

I assume the note (last sentence) applies to flat space time? The curvature scalar remains the same, also in non flat space time?

Two reference frames moving relative to each other at a constant velocity are related by a Lorentz transformation. As a result, the invariant properties of the Riemann curvature tensor will remain the same in both reference frames. This means that all inertial observers will measure the same...

Is there proof of the correctness of the de Broglie wavelength for macroscopic objects? The proof based on the analogy with light for elementary particles is familiar to me.

Is the Heisenberg Uncertainty Principle (HUP) applicable to macroscopic objects? A football, for instance, is composed of an enormous number of particles. Can the applicability of the HUP to a macroscopic object like a football be demonstrated through statistical methods, starting from the...