All Questions

Say you set up an experiment with an inclined plane, and a cylinder rolling down the plane. Let's also let the experiment happen in a vacuum, such that there is no air friction. However, let there be ...

If I have a situation like this Where my blue thing is wall and the yellow thing is the ground. If both were to be smooth then they will exert a contact force only normal to them which I have ...

If photon wavefunctions are omnidirectional and don't have a definite size, how comes those from the Sun don't all collapse on Mercury and some do actually reach Earth ? I understand that ...

When an object moves in a circle, there's an acceleration towards the center of the circle, the centripetal acceleration, which also gives us the centrifugal force (since $F = ma$ is the equation for ...

This question is from first order circuit and under the heading of source free RL circuit (https://i.stack.imgur.com/SY1L6.jpg)

In laser when assembly of atoms is influenced by em wave, only few of the atoms get excited not all? why it happens

Confirmed experimental data is the looked after answer. Pure, simple , straight forward. edit: beamed or bottled/cold neutrons, either works.

A rock is thrown upward from level ground in such a way that the maximum height of its flight is equal to its horizontal range R. At what angle $\theta$ is the rock thrown? I used range formula $R=\...

The question concerns the double-slit experiment with collecting the data to register through which of the slits every single photon has passed. As I understand, in this case, when the photons are ...

Gaming mice have very smooth bottoms, but gaming mouse pads have a very rough surface, much more than regular mouse pads. How can it be that a smooth surface on a rough surface have less friction ...

In the example below, the author derives the angular velocity of the xyz frame with respect to non-rotating earth. I failed to understand how he derived the angular velocity? What does the author mean ...

There is a lot written on the moon affecting the Earth's rotation but not so much the other way around. I know that moon has its own rotation: Tidal locking is the phenomenon by which a body has ...

Consider a complex scalar field $\psi(x)$ with Lagrangian density $$ \mathcal{L} = \partial_\mu\psi^* \partial^\mu\psi - M^2\psi^*\psi. $$ Expand the complex field operator as a sum $$ \psi = \int \...

I’ve read that the wavelength of macroscopic objects is so small that it’s effects are negligible so the object can be described with classical physics, and that decoherence causes quantum effects to ...

The investigation is experimentally verifying Poiseuille's equation. The independent variable is the changing pressure and the dependent variable is flow rate. My experiment plan is having a simple ...

Will somebody give me the exact decimal form of 23 hours, 56 minutes and 4 seconds?

I'm not a physician, What about the chance to make a radiotelescope of today communicate with a radiotelescope of the past or of the future ? The speed of light is k bigger than the speed of the ...

I've recently been looking at the quantum mechanical description of a charged particle in an EM field and have come across this classical Hamiltonian: $$H = \cfrac{(\mathbf p - q\mathbf A)^2}{2m} + q\...

If we take atomic hydrogen with similar spin together, can we hold it in balloon? I know, that the atom is hydrogen is reactive. But when all atoms will have similar spin, reactions between them will ...

I would really appreciate a confirmation about the following statements about general relativity, which I deduced after a self-learning process (but which I am not sure of) 1) If there is no ...

I'm studying the photoelectric effect where it turned out that the kinetic energy of the emitted electron was dependent on the frequency of the u.v. light and not its intensity. It was previously ...

I was reading the following paper by my guide and I encountered the following doubts. Consider the following two situations This is the case of the static contact angle. In this case, the solid ...

A block is placed on the trolley. It is found after calculations that the block is at rest with respect to trolley when it is accelerating and when acceleration is zero What will be the motion of ...

The momentum of a photon is $\ p=E/c.$ When a photon reflects off a mirror, it is elastic scattering. Elastic scattering should keep the energy of the photon. But radiation pressure states, that ...

So, I am making an essay explaining planet-hunting techniques. And while I do get how astronomers measure the semi-major axis of a planetary orbit (using Kepler Laws), I don't get how they measure the ...

I’m trying to get through 11-6 section of Feynman’s Lectures on Physics, Vol 1, particularly explanation of acceleration vector calculation in his example: It’s clear that acceleration ...

In Gibbs free energy, entropy is treated as a sort of energy. The increase of entropy can generate work and release energy. However, normally energies are associated with actual forces. Light is due ...

Given $N$ distinguishable quantum particles in the canonical ensemble, we can estimate the probability of finding one of those, labelled by $j$, in a certain position $x\in\mathbb R$ by computing \...

Is there any difference between electrical conductivity and optical conductivity? How to explain it physically and is there any method available to connect them mathematically? If I calculate carrier ...

I have read that light is an electromagnetic wave. Every ray of light has a specific wavelength. The colour perceived by any observer is dependent upon the wavelength of the incident light. What I ...

I know how to do tree level calculations, I just want to copy expressions for Standard model interactions rather than doing them all myself. Is it possible to find them in a table somewhere ?

At what distance above the surface of the earth is the acceleration due to the earth's gravity 0.980 m/s^2 if the acceleration due to gravity at the surface has magnitude of 9.80 m/s^2? Radius of the ...

For a given amount of a chemically defined homogeneous fluid, the equation of state is often represented as $$f(p, V, T) = 0.$$ But, does this include all the possible states that the fluid can be in?...

I don't understand what does it mean for 'Euclid's Test' when they talk about negative pressure Using Euclid’s test for a hypothesis of examining its implications, one finds that negative pressure ...

In today's Relativity and Gravitation class, my prof was discussing about Riemann-Christoffel Tensor and he derived it. But in the end he told that there are many ways one can derive the Riemann ...

I just had this really weird question. On average, how much energy is lost, when one air molecules hits another air molecule? By air molecule I mean one molecule of the gases in the atmosphere. On ...

While preparing for an exam I found a problem where one has to find the composition of hadrons given their quantum numbers. $$\text{ (Charge, Baryon number, Strangeness, Charm, Bottomness)=(Q,B,s,c,b)...

The equation to calculate gibbs free energy includes the absolute temperature of the system. However isn't it the energy needed to raise temperature independent of the initial temperature? Why does ...

I am being troubled by this question: A non stretchable thread with masses $m_1$ and $m_2$ attached to its end is thrown over a pulley block. We begin to lift the pulley block with acceleration $...

Can I use Lagrangian mechanics to model a $n$-simple pendulum system where $n$ stands for any natural number? If so, please tell me how.

To calculate the ADM mass, one has to specify a closed surface inside which all the mass is located. Are there any ways to calculate the mass inside a closed surface outside of which other mass still ...

If the space/universe is expanding what will happen if we try to compress it? Is it possible?

I already asked this question on the math stack exchange but even if it is a math question it is something common in physics so I think it is more relevant to ask it here. https://math.stackexchange....

I recently read an article about "groundbreaking Australian research in the hunt for dark matter", in which it said: We use highly purified crystals to detect dark matter. These crystals react when ...

I'm working on an exercise which asks me to determine the canonical fields, and their equations of motion, of this invariant action: $$ S = \int d\tau \sqrt{g_{\tau\tau}}\left( \frac{\tilde m}{2} g^{\...

Suppose, we have a simple capacitor/battery setup like that shown below. The battery is used to charge up the capacitor. After the capacitor is charged, there will be equilibrium, the field of the ...

Let's say I have a particle in a uniformly acclerated motion such that $$ a_\mu a^\mu = -g^2, \quad g > 0\ {\rm and\ constant} \tag1 $$ I want to prove that any signal coming from a apace-time ...

What I am asking is that $\psi_1 \otimes \psi_2$ and $\psi_2 \otimes \psi_1$ are obviously different states. However, theoretically a measurement can be done that these to states will give two ...

d1 = 350km at xkm/h d2 = 120km at x-15km/h suppose time taken for each part of the journey is the same. What is the average speed for the second part of the journey?

A small particle attach to the one end of string. The other end of the string is attached to the fixed point. The mass is raised such that the string is horizontal released. The locus of the tip of ...