Particle Definition and 1000 Threads

I find a exercise in Leonard Susskind's book Classical Mechanics the Hamiltonian of a charged particle in a magnetic field(ignore the electric field) is $$H=\sum_{i} \left\{ \frac{1}{2m} \left[ p_{i}-\frac{e}{c}A_{i}(x) \right]\left[ p_{i}-\frac{e}{c}A_{i}(x) \right]...

Hello! In most of the modern mass measurements in a penning trap, they cool down the degrees of freedom of the ion (the 3 eigenmotions) using resistive cooling, in which they couple an external circuit to some of the electrodes of the trap and the ion is cooled down to the temperature of the...

This question is very confusing since I don't see two distinct particles that are exerting a gravitational force on each other. Also to complicate matters, a gas is made of many individual particles and I don't know how to determine the gravitational force on a single particle from so many other...

Consider the system of the mass and uniform disc. Since no external forces act on the system, the angular momentum will be conserved. For elastic collision, the kinetic energy of the system stays constant.Measuring angular momentum from the hinge: ##\vec L_i = Rmv_0 \space\hat i + I \omega_0...

Curious about this (https://en.wikipedia.org/wiki/Particle_accelerator) which indicates diminishing returns on new particle accelerators. However to uncover new physics, presumably you need to keep increasing the Lorentz factor by the roughly 10x trend here: So is this hopeless?

I have read that if the exchangeparticle of an interaction has even spin then the force between them is attractive if the charge is equal (gravitation) and repulsive if the charge is not equal. Is this wright?

Two forces each of size 8N, have a resultant of 13N. a) Find the angle between the forces b) The two given forces of magnitude 8N act on a particle of mass m kg, which remains at rest on a horizontal surface with no friction. The normal contact force between the surface and the particle has...

I tried to resolve this problem with youtube tutorials help, but, i have a many wrong results. The teacher says that the problem requires critics points, so i know that for that points i need a second grade ecuation, but i don't know how interpreter that points. My results: PD: I don't know how...

I think I made an error somewhere. In ##[0,a]## I let ##\varphi(x) = \varphi_1(x) := p\sin{kx}## whilst in ##(\xi, \infty)## I let ##\varphi(x) = \varphi_2 (x) := re^{-\gamma x}##, and the constraints at ##x=\xi## are \begin{align*} \varphi_1'(\xi) = \varphi_2'(\xi) &\implies pk\cos{k\xi} =...

I was going to put this in the homework forums, but on second thoughts it's more conceptual so perhaps here is better. It's about problem 4, chapter 6 of Wald. Part (a) is fine, $$u^a \nabla_a u^b = \frac{\xi^a}{(-\xi^c \xi_c)^{1/2}} \left( \frac{\nabla_a \xi^b}{(-\xi^c \xi_c)^{1/2}} +...

A table with smooth horizontal surface is fixed in a cabin that rotates with a uniform angular velocity ω in a circular path of radius R. A smooth horizontal groove AB of length L(<<R) is made on the surface of the table. The groove makes an angle θ with the radius OA of the circle in which the...

I've been stuck starting anywhere with this. I need to finish this class for graduation and i'd like a safety net of a passing grade with this.

Hello! I am taking a course on Electroweak & Strong Interactions (you could equally call it Standard Model I) and I find it absolutely fascinating! 😍 We studied how weak interactions violate parity, introduction to QCD, flavor physics (CKM matrix, CP violation, …) and neutrino physics...

Hi all Another random, kinda open-ended question here. Sorry for that. I found myself reading about atomizing nozzles in oil burners, and got curious about the physics of atomized sprays. I didn't have much luck researching this on my own, so I'm turning to you all. It was the kind of situation...

Hi, I have to find the motion of a particles ##(x,y,z)##. However, I'm not sure where to begin. Is it correct to split the problem and first find what's the motion in the x direction then y and z. For exemple, ##m \frac{d^2x}{dt^2} = -kv_{0x} + qv_{0x}B sin 90 ## ##m\int\int...

There is a particle with mass $m$ sliding from the hoop with radius R. Its asked to find the height of the hoop which the particles falls. Now I did the hard part (I guess) and find the Lagrangian of the system. Which is given as $$-mR\dot{\theta}^2 + mg\sin\theta = \lambda$$ and...

In an electric field ##E## if the energy of charged particle (ion) is formulated as ##W=qEr## where ##r## is the distance, how the number of particles is estimated?

"A single neutrino has a mass of about 2 billion-billion-billion-billionths of a gram ... A neutrino with 6.3 petaelectronvolts (PeV) of energy ... is equivalent to the energy of a swarm of 6,300 mosquitos [moving at 1mph] ... [or one mosquito accelerated to] Mach-8.2..."...

To me, the ##K## obtained by solving the Schrodinger equation and the de broglie wavelength seem two completely unrelated quantities. Can someone explain why have we equated ##K## and ##\frac{2\pi}{\lambda}##. Also, isn't writing ##p = \hbar K## implying that eigenstate of energy is also an...

(a) Let the center of the concentric spheres be the origin at ##r=0##, where r is the radius defined in spherical coordinates. The potential is given by the piece-wise function $$V(r)=\infty, r<a$$ $$V(r)=0, a<r<R$$ $$V(r)=\infty, r<a$$ (b) we solve the Schrodinger equation and obtain...

a proton is confined to an infinite potential well of width ##a=8fm##. The proton is in the state $$\psi(x,0)=\sqrt{\frac{4}{56}}sin\Big(\frac{\pi x}{8}\Big)+\sqrt{\frac{2}{56}}sin\Big(\frac{2\pi x}{8}\Big)+\sqrt{\frac{8}{56}}sin\Big(\frac{3\pi x}{8}\Big)$$ (a) What are the values of energy...

The rod itself should have 3 translational+2 rotational DOF. The particle on top of the rod has one additional DOF. So total should be 6. But answer given is 4. What I'm thinking wrong?

Hello! This is probably something simple but I am getting confused about it. Assume we have an electric field along the z axis given by ##E = -kz##, with ##k>0##, so the field on both sides of the xy-plane points towards the origin. Let's say that we have a positively charged ion at the origin...

Hi hi, I would like clarify this, I'm looking for models that can support to a particles have several properties, I know classic physics, my main problem, if we have a fluid with movement forces and heat, the classic model don't support this, only independent from each other... So, a lot of ppl...

Unfortunately, I have no idea about a possible solution.

Here are the quotes https://www.symmetrymagazine.org/article/show-your-affection-with-physics-valentines , I find them funny except for the last one is hurtful, I shouldn't say such a thing for someone on a valentine's day because they would care about the valentine's day, personally I find it...

(a) I guess I should find ##C_n## by normalizing ##\psi_n##. $$∫_{∞}^∞|C_nψn(x)|^2 dx=C_n^2 \frac{2}{a}∫_0^a sin^2(\frac{πnx}{a})dx=1$$ $$C_n^2 \frac{2}{a}[\frac{a}{2}−\frac{a}{4πn}sin(\frac{2πna}{a})]=1⇒C_n=1$$ (b) $$Hψ_n(x)=\frac{-ħ^2}{2m}\frac{\partial^2}{\partial...

Suppose a particle is moving around a circular track of radius R at speed v. To bend around a circle some agency has to exert an acceleration towards the center of the circle. I analyze the forces acting on the particle, its weight and the normal force and there is no acceleration in the...

I tried 1. using the Lagrangian method: From ##y=-kx^2## I got ##\dot y = -2kx \dot x## and ##\ddot y = -2k \dot x^2 - 2 kx \dot x##. (Can I use ##\dot y = g## here due to gravity?) This gives for kinetic energy: $$T = \frac{1}{2} mv^2 = \frac{1}{2} m (\dot x^2 + \dot y^2) = \frac{1}{2} m (\dot...

Hi everyone, I was hoping the internet would be filled with video lectures since lots of universities have been forced to conduct online teaching. However, that doesn't seem to be the case. Therefore I was hoping that some of you know of some great video lectures for nuclear and particle...

I have very little knowledge on engineering or electrical engineering at the moment, which is why I would like to learn more about it. I have read many articles on them but I am still unclear of some of the materials required for something like this. I am very unqualified to be discussing...

Suppose I have 100 identical boxes of length L and the coordinates are x=0 at one end of the box and x=L at the other end, for each of them. Each has a particle of mass m. V=0 in [0,L], while it's equal to infinity in the rest of the regions. If I make a measurement on position of the particle...

Help please

Hi, I have a particle on a parabolic surface $$y = Ax^2$$ and I have to show that the frequency is $$\omega = \sqrt{2Ag}$$ I don't know how to deal with a parabola. I don't think I can use the polar coordinates like a circle. I don't see how to start this problem and in which coordinates...

Hi, Several times I encounter the argument that there is a "problem" with the masses in the Standard Model that we try to "understand". From the one side, you have people who ask why the neutrino masses are so small, and from the other side they ask why the top quark mass is so large. The...

Suppose we have two charged particles A and B released in the center of the Mirror (where the field is minimum). If A's velocity direction is parallel with the Magnetic field of the mirror and B's velocity is perpendicular with the field, then which one is going to get trapped, or escape, or...

While solving question 1.13(see the attachment) from Irodov, I was doing this: $$\int_{0}^{\tau}(\vec{v}-ucos\theta) dt=l$$, and $$\int_{0}^{\tau}\vec{v}cos\theta dt=u\tau$$. Solving this gave the answer. However, while solving these 2 equations, I only used the magnitude of ##\vec{v}##, and...

Here is the solution I have been given: But I really don't understand this solution. Why can I just add these two exponential factors (adding two individual partition...

Hi all, I interested in how can I get low of motion in for orbiting particle in a uniform magnetic field $$\frac{d\vec{r}}{dt} = \vec{\omega}\times\vec{r},\qquad \vec{\omega} = \frac{e\vec{B}}{mc},$$ Of course, rotating about z' axis is very simple. \begin{equation}\label{eq:K}...

I have done a bit of googling but cannot find anything in this regard at all. It seems to all be "thought of" (rather than explained) by the Huygens–Fresnel principle and other spin offs. Can anyone point me to a particle explanation of diffraction for sound waves? Or does anyone here have...

So first I did the vector stuff. r2-r1= 1.3 i hat-47.5 j hat-14.5 k hat magnitude = 49.68 magnitude squared = 2468.19 Now plugging it all in... F=9E9*6.3E-3*2.8E-3/2468.19=64.322 y vector, -47.5/49.68=-0.956119 j hat Multiply this by force and I get -61.499 but answer should be -36.14

During particle annhilation the rest mass of the particle pair gets converted into momentum with zero time component ie. light. As the pair is colliding do their rest masses decrease and get converted to momentum as a function of distance? Or do they instantaneous annihilate in a discrete interval?

There is something unusual about water. Without atmosphere, water can't exist. It's as if water is part of atmosphere. In vacuum, liquid water can't exist. What other things like water where it needs other aspects like atmosphere to exist? And what is the analogy of water in particle physics...

From one point of view the charged particle is accelerating and should emit electromagnetic waves. But from the equivalence principle, I think, it should not. Does anybody know the answer?

I couldn't prove the first one but i tried to find the period F = -dU / dx = - d( U0tan^2( x / a ) ) / dx = - U0 ( ( 2 sec^2( x / a ) tan( x / a ) / a ) with F=d^2x/dt^2, tan(x/a)=x/a we have d^2x/dt^2 + U0 ( ( 2 sec^2( x / a ) ( x / a^2 ) =0 from there i don't know how to handle the...

Hi, I’m wondering if someone can help me understand this question. I can find a resultant force/vector when given an initial angle but I’m stuck here when the only information is the two magnitudes. I think I’m solving for the unknowns but a little lost on how or what equation I should be using...

I'm reading this article on Dark Matter and at some point the authors say '' if the LKP [Lightest Kalusa-Klein Particle] is to account for the observed quantity of dark matter, its mass [...] should lie in the range of 400 to 1200 GeV, well above any current experimental constraint.'' My...

The Lorentz's force acting on a charged particle perpendicularly "hitting" a magnetic field will be directed upwards, and generally directed towards the center of the circumference traveled by this particle, and so will cause a centripetal acceleration to keep it in a circular motion. By...

I have the equation but I am unsure of what my r min would be. Is it the sum of the radii or the difference? I am also confused on what z1 would be. I am fairly sure z2 is the atomic number of Fe(26) but I am unsure of this as well. Edit: I just read that z1 could be 2, is this correct?