Momentum Definition and 1000 Threads

I am having some difficulty understanding what "recoil" really is with respect to momentum, force, and and time. On the one hand, momentum is considered to be the product of mass and velocity or perhaps the product of the sum of masses and some velocity, or some variant of P=mv, where P is a...

I think the solution to this problem is a straightforward calculation and I think I was able to make reasonable progress, but I'm not sure how to finish this... $$\begin{align*} \vec{P}&=-\int dx^3 \pi \nabla \phi\\ &= -\int\int\int dx^3\frac{dp^3}{(2\pi)^3 2e(p)} \frac{du^3}{(2\pi)^3}...

I don't know if the value for distance between protons given in the homework is right (##d = 74.14 pm##). Indeed, on the following link : https://brainly.in/question/7147660 , they take a distance equal to ##d = 4\times10^{-10} m##. In all cases, the same formula is applied ...

Hi, Since this is a question about COAM (Conservation of Angular Momentum), I will assume I can leave out the part on translation and just use the formula below: ##Initial Angular Momentum= Final Angular Momentum## whereby ##I = \frac {1}{12}ML^2## (of rod) So, ##\frac {1}{12}ML^2(1.5)=\frac...

Suppose object1 with mass m and velocity v has collided with a block. Also, object2 that has identical shape and dimensions with mass m/2 and velocity 2v has collided to that block. Since the momenta of two objects are identical but the kinetic energy of object2 is twice: Are the forces between...

I encountered a weird conflict between my thought process and that of author's solution in book: The common viewpoint of both of us were invoking conservation of energy of this SHM system But the author proceeds to solve it using conservation of momentum, taking the new mass added to system as...

Hello everybody! I am working on a code in which I need to study the dependence of ##<p_T>## vs ##p_L## (the average transverse momentum and the longitudinal momentum of a particle). I am looking for references, papers, books, etc. concerning this topic, but I have not been so lucky. My...

In the paper below I've seen a new method to solve the quantum harmonic oscillator Introduction to the Spectrum of N=4 SYM and the Quantum Spectral Curve It is done using the concept of quasi momentum defined as $$p = - i \frac{d(\log \psi)}{dx}$$ See pg 7,8 Is this well know? is it discussed...

Let's say we are in outer space.Suppose I have 2 metallic balls A and B with initial velocity 0 and same mass M and a baseball bat.Let's say I hit the ball A with force F and ball B with F' in such a way that F>F'.Ball A attain final velocity V in time T and ball B attain final velocity V' in...

Light is a funny thing. If it could move slower it would have more momentum, not less! How weird is that? Or is that all wrong? I would appreciate comments on that.

I am trying to derive the radial momentum equation in the equatorial Kerr geometry obtained from the equation $$ (P+\rho)u^\nu u^r_{;\nu}+(g^{r\nu}+u^ru^\nu)P_{,r}=0 \qquad $$. Expressing the first term in the equation as $$ (P+\rho)u^\nu u^r_{;\nu}=(P+\rho)u^r u^r_{;r} $$ I obtained the...

I want to ask why is it that we use gauge pressure instead of absolute pressure in CV analysis for momentum conservation of fluids. I did read that because P(atm) would be present everywhere so it won't have a net effect on the CV but it's highly non intuitive as I can't apply force balance on...

So to start off, the piece that hits the ground first is the smaller piece. So I can form the equations where: where ##8(u_{8kg})= m_{1}v_{1}+m_{2}v_{2}## ##m_{1}+m_{2}= 8## After 2 seconds, ##30 = v_{1}(2)+\frac{1}{2}at^{2}## ##v_{1}= 5.2m/s## ##(30-16) = v_{2}(2)+\frac{1}{2}at^{2}## ##v_{2}=...

I have a feeling that topics related to the Energy Momentum tensor are the most difficult part when learning Relativity. At least to me, it seems that the textbooks I'm reading assume that readers have a previous knowledge on some other area, maybe it's classical mechanics of fluids or something...

Hi, I'm a bit confused about Bloch functions. This is what, I think, I understood: can someone please tell me what's wrong? From Bloch's theorem we know that the wave-function of an electron inside a periodical lattice can be written as ##ψ_k(r)=u_k(r)e^{ik⋅r}##. We hope that far from a lattice...

I think the answer is ##\frac{mV}{M}## but I am not sure. Won't the cylinder tries to rotate due to the collision at one end? Is this anything related to Angular Momentum? The Answers given were,

Hi Folks, This is a super simple physics problem that I just cannot understand when and where to implement the difference. Here is the problem: A 20kg Cart is moving horizontally along a friction-less track with a speed of 4 m/s when a 10 kg bag of sand is quickly placed on it. What is its new...

I suppose that the principle of conservation of angular momentum holds also for a cloud of particles weekly interacting at low pressure, density and temperature. And it should be still applicable when the particles or the atoms would start condensing and forming fusion products or simply solid...

Hi, I understand and I'm sorry that there are going to be many loopholes in what I'm trying to put together and that too without any mathematical formulation but I don't even know where and what to start with. Suppose we have a finite length insulated hollow cylinder filled with with air at 1...

There is a cornering maneuver in rallying called the "Scandinavian flick" or the "pendulum turn". It involves steering away from the corner before actually steering into the corner. This creates a pendulum effect which makes the car turn more sharply into the corner. Sorry for the poor video...

The momentum operator for one spation dimension is -iħd/dx (which isn't a vector operator) but for 3 spatial dimensions is -iħ∇ which is a vector operator. So is it a vector or a scalar operator ?

I'm reading through "University Physics 14th edition" by Young and Freeman. Section 10.5 on angular momentum for a rigid body around a fixed axis of rotation is derived as L = Iω. However, it shows that this is only the case for the fixed axis of rotation being an axis of symmetry. In section...

Even if a beam of light strikes a reflective surface at an angle 'A', the change in momentum should be 2mc, P=2IcosA/C but I find it P= 2Icos^2(A)/C.

If a copper wire is wound around a piece of iron, nickel or cobalt, and a voltage is applied to the wire, it takes a longer amount of time for the current to reach its maximum value, than if the iron were replaced with a different material, such as glass— a phenomenon known as inductance. My...

Is it appropriate to say that within classical physics the general form of Newton II is the Cauchy momentum equation? This equation applies to an arbitrary continuum body. Therefore it is more general than the common form of Newton II which applies basically to point masses and centers of mass...

In this video, around 2:28 He explains Earth maintain its same angular momentum even after sun disappears. I didn't get it. How Earth maintain its same angular momentum even after sun disappears?

a) Kepler's first law states that a planet like Earth displays an elliptical orbit with the sun in focus. Using M = dL/dt, prove that a planet cannot leave its plane of orbit. Note: M here is an externally applied torque that the sun exerts on the planet. diagram of the situation described b)...

Suppose there is a photon with momtum p=h/lambda moving in the positive x-direction. Suppose it collides with an electron at rest and is completely absorbed by the electron, and that after the collision, the electron moves to the right with the same momentum of the photon. This seems...

When two cars crash into one another they generally come to a stop, yet we are told momentum cannot be created or destroyed. Where did their momentum go? It seems like the kinetic energy went into the damage in the vehicles but apparently that has nothing to do with momentum?. Thanks...

Problem Statement: Are this 3 topics comes under laws of conservation of momentum? Relevant Equations: Are this 3 topics comes under laws of conservation of momentum? Are this 3 topics comes under laws of conservation of momentum: energy lost due to impact, inelastic impact, purely elastic...

Suppose that we have two balls (1) and (2) with the masses m1 and m2 and velocities v1 and v2, respectively. Furthermore, suppose that their momentums and kinetic energies are not the same so that P1>P2 and K1<K2. Which ball is more dangerous in hitting a person.

I calculated force vector by differentiating momentum vector.Since acceleration and velocity vectors are at45°,therefore force and momentum vector are at 45°.But i am not able to find the time at which it will take place.I tried F vector.P vector=FPcos45° but i am not getting from it.I also used...

Considering pilot wave interpretation, a singular particle measurements are fully defined (?) by knowing its wave function (a pilot wave) and the position of the "particle" (some hypotetical point particle riding on the wave). This should provide some sort of "realistic" explanation of how a...

I've come up with the following causes: - air resistance - parallax - during the collision, some of the kinetic energy gets converted into thermal energy. - invisible deformations But I'm not sure which would be the biggest effect on the total momentum change. Are there any other reasons that...

3. Find the hamilton equations 4. using 3. prove the the angular momentum in the z axis ##L_z=m(x\dot y-xy\dot)## is preserved. I got in ##3##: How can I prove 4?

Okay so I begin first by mentioning the length of the well to be L, with upper bound, L/2 and lower bound, -L/2 and the conjugate u* = Aexp{-iz} First I begin by writing out the expectation formula: ## \langle p \rangle = \int_{\frac{L}{2}}^{ \frac{L}{2} } Aexp(-iu) -i \hbar \frac{ \partial }{...

I tried out the F=Δp/Δt equation and i came up with a change of momentum of the box-bullet fusion (M+m)V-0, but the textbook says otherwise (using a change of momentum of JUST the box itself, excluding the bullet). According to the textbook, the correct change is MV-0, without the added mass of...

What I know is the following: The total angular momentum of the nucleus is just the total sum of the angular momentum of each nucleon. If the nucleons are even the total angular momentum in the ground state will simply be ##0+##. If the odd number of nucleons is close to one of the magic...

Although I've read many papers that propose a relation between action and entropy, I've been told that there is no generally accepted relation in physics. But how/why are these concepts unrelated? What about nobel laureate Frank Wilczek? He proposes that entropy and action are closely related...

Hi! I am trying to change the hydrogen ground state wave funcion from position to momentum space, so i solved the integral Ψ(p)=(2πħ)^(-3/2) (πa^3)^(-1/2)∫∫∫e^(prcosθ/ħ) e^(-r/a) senθ r^2 dΦdθdr and got 4πħ(2πħ)^(-3/2) p^(-1) (πa^3)^(-1/2) I am [(ip/ħ-1/a)^(-2)], which according to the...

I managed to solve the exercise, but I'm not sure if it's correct or not. I came up with this: p1+p2=P then p1+p2=0 then p1=-p2 and therefore i solved for p1 so that i could find p2, which is the NEGATIVE value of p1, according to the previous equation. I'm just concerned about this because...

A cyclist coasts along a road, he drives across a small puddle of water, after which the wheels leave wet lines on the road. Now we concentrate our attention to the linear momentum of the water on a wheel. It decreases. Momentum is conserved, so what got the momentum that the water had?

Part (iii) is the part I am stuck on and is a 5 mark question. I have some idea of how to attempt it shown below momentum is conserved so mux = mvy + mvz (where ux is the initial velocity before the collision of ball x, vy is the velocity after the collision of ball y and vz is the velocity...

I was wondering why in the video the moment of inertia for the clay ball (upon collision) was simply 1ml^2. That is the constant for a hollow cylinder. The problem specifies that the object is a ball, so the cylinder classification makes no sense, and also I'm pretty sure clay is rather dense...

The fig. 1.1(a) is a mass m attached to a spring that is fixed to a wall. I don't understand what does "a sudden momentum impulse" means. Is it an external force o what? I imagined that the new equation of motion would be md^2x/dt^2+dp1/dt-kx=0 md^2x/dt^2+mdv1/dt-kx=0 is this the equation i...

So, I was reading my textbook in the section regarding net torque, and they gave an example of a seesaw with one person at each end, and they said that there is a net external torque due to the force of gravity on each person. I completely understand that; however, when I was reading another...

Okay so the first thing I did was was find the height of the apex. I found this by finding the x and y components of Vo: Vox = VoCos(θ) = 22cos(59) = 11.33 m/s Voy = VoSin(θ) = 22sin(59) = 18.86 m/s Using the initial velocity of the y component I found the time it took to reach the apex: t =...

Is there a relationship between the momentum operator matrix elements and the following: <φ|dH/dkx|ψ> where kx is the Bloch wave number such that if I have the latter calculated for the x direction as a matrix, I can get the momentum operator matrix elements from it?

Lets consider the angular momentum tensor (here ##m=1##) \begin{equation} L^{ij} = x^iv^j - x^jv^i \end{equation} and rortational velocity of particle (expressed via angular momentum tensor) \begin{equation} v^j = \omega^{jm}x_m. \end{equation} Then \begin{equation} L^{ij} =...

If an object is moving it has momentum .. but if the frame of reference is altered so the speed matches, the momentum apparently vanishes (?!). Likewise with apparent inertia during acceleration of an object - similar acceleration of the frame can radically alter the perceived affect. Can...