Momentum Definition and 1000 Threads

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...

If i were to take one point as my origin and draw the two momentum, one for the initial collestion and one going from the wall after, from the origin point, then drawing horizontally i would get the answer as B as the resultant? Should i assume that for any resultant vector the direction can...

I had a question about the equation (1/2)mv^2... Why is the velocity squared? Why not simply (1/2)mv? Does it have anything to do with the intrinsic angular momentum ie does the intrinsic angular momentum change in anyway as velocity increases in a particular reference frame leading to the...

So if we define point 1 at the entrance and point 2 at the exit, then we can write out Bernoulli's equation along a horizontal streamline as such: p_1 + \frac{1}{2}\rho v_{1}^2 = p_2 + \frac{1}{2}\rho v_{2}^2 = p_{atm} One question is: won't there be p_atm also contributing to the static...

For this question, this is my working. The main issue is I cannot figure out where the factor of \frac{1}{2} comes from. So I consider a control volume right around the propeller (in the frame of reference of the propeller) and I apply R(-->) Force = Change in Momentum Flux F = \dot{m_{o}}...

Solving using Linear Momentum: M vb2/2 = M g 2L vb = 2√(g L) m v = m v/2 + M (2√(g L) ) v = 4 M √(g L) / m Note: I see from the answers - that this is correct. -------------- Next, I tried to solve it via Energy conservation point of view. M vb2/2 = M g 2L vb = 2√(g L) m v2/2 = m v2/8 + k...

I don't have too much of a clue of how to begin the problem. I first wrote the angular moementum of the system of particles: →M=∑mi(→ri×→vi)M→=∑mi(r→i×v→i). Then I know that the angular momentum from of the moving reference frame would have the velocity as the sum of the velocity of the frame...

Hello! Can someone point me to some table or functional form of the distribution of proton momentum inside deuterium? I found it for some high A (even for A=3), but can't find it for deuterium. Thank you!

n is the principal quantum number. l is the angular momentum quantum number. ml is the magnetic quantum number. The possible values of l are 2, 3, and 4. I'm not sure if l can be equal to 4. On the answer key, it shows l = 2, 3.

Why is angular momentum conserved for a charge in an electric field?

Hello, I am an undergrad and am in an introductory level astrophysics course. I have a bit of confusion that I didn't know where to get help from so I made an account here. Please let me know if I miss some common etiquette or something... I don't understand how the slingshot maneuver...

My personal course of study in quantum mechanics hasn't brought me this far and so this question may be incredibly naive, but it has still been troubling me. If the energy of a photon is E = (hbar)(omega) and the units of hbar are J*s (obviously), then how can a photon have no mass if a J is...

1)In the first case the mass changes, in this manner: m1= m1i - k Δt impulse-momentum theorem: F1Δt=Δq FΔt=m1V1-m1iV1i I now can replace m1 with its definition and obtain: F1Δt= (m1i - k Δt)V1 -m1iV1i = m1iV1i - kΔtV1- m1iV1i = - kΔtV1 It is possible to remove Δt as it appears in both...

My only issue is what this would look like. I can't draw a respective picture.

That said, my approach was to determine the energies and 3-momenta at the center of momentum reference frame for each particle, with a fixed s, and check it corresponds to each one of the above, but I'm having some trouble proving that, for example, E_A=\frac{s+m^2_A-m^2_B}{2\sqrt{s}}. I've...

Homework Statement From Griffiths GM 3rd p.266 Consider a free particle of mass ##m##. Show that the position and momentum operators in the Heisenberg picture are given by$$ {\hat x}_H \left( t \right) ={\hat x}_H \left( 0 \right) + \frac { {\hat p}_H \left( 0 \right) t} m $$ $$ {\hat p}_H...

When do we use L=r x P and L=I x Omega (angular velocity)? in old 8.01x - Lect 24, I pasted here link of the lecture, which will take you at exact time (at 27:02)he says "spin angular momentum" in classical physics lecture and why? I expected to hear "angular momentum" vector. Normally...

In https://www.sciencedirect.com/science/article/pii/S0378437109010401, the author claims that the interference pattern obtained in the double-slit experiment does not need a wave description of matter, and can be accounted for by the "quantized momentum transfer" from the slits to the electron...

Homework Statement A particle with mass M and speed v along the positive x-axis hits a stationary mass m. Two particles, each with mass µ, emerge from the collision, at angles with respect to the x-axis. (a) Write the equation for conservation of the 4-momenta, for arbitrary angles θ_1, θ_2 of...

Hi, once again I'm probably asking a question that is more about human physiology than physics (I recently asked a question that had to do with hearing). I found a (definitely too hasty) reference to a ballistocardiograph in a high school textbook. So I got curious about the way this apparatus...

I have a problem in mechanics. On the wedge and block only the gravisational force (mg) is exerted (and there is no friction in this system). What is asked in the question is the final velocities of the wedge and the block (vB, vK). The velocity of the block is conserved when it reaches at the...

I'm interested in knowing the ratio of momentum for a neutrino vs. a photon when both have the same energy. Alternatively, my spaceship engine can release 1GW of either a photon beam or a neutrino beam. How much relative thrust will the neutrino beam give me for the same energy (and power) as...

1. A system consists of a disk rotating on a frictionless axle and a piece of clay moving toward it as shown above. Outside edge of the disk is moving at a linear speed of V and the clay is moving at speed v/2. How does angular momentum of system after the clay sticks compare to the angular...

Given the figure, how can i arrive to this formula knowing that angular momentum is conserved? I know that p = mv and L = p x r. So the initial momentum will be L1 = mV x R and the final momentum will be L2 = mv x r. I am not sure how R will equal to b since the distance between the...

Homework Statement This question was on a recent AP Physics 1 exam as a multiple choice; "Three air track gliders, shown to the right all have the same mass M. Gliders 2 and 3 are initially at rest. Glider 1 is moving to the right with speed v. Glider 1 collides with glider 2 and sticks to it...

I understand that in a system composed of two articles, the total angular momentum is: J = J1 + J2 From the operators: J^2, Jz, J1z, J2z，J^21z，J^22z, I get two possible sets of operators that commute: {J^2, Jz, J^21z, J^22z} and {J^21z, J^22z, J1z, J2z} What I don't understand is why the...

Hello forum. I have a HW question that I don't fully grasp just yet. It was multiple choice and somehow I guessed the right answer based on the work I did complete, but I want to know how to get to the solution and which steps I'm leaving out. I'll follow the format to write out the...

Homework Statement Two ice skaters have masses m1 and m2 and are initially stationary. Their skates are identical. They push against one another, as in Figure 7.11, and move in opposite directions with different speeds. While they are pushing against each other, any kinetic frictional forces...

Homework Statement A fireworks rocket is moving at a speed of 45.0 m/s. The rocket suddenly breaks into two pieces of equal mass, which fly off with velocities v1 and v2. What are the magnitudes of v1 and v2? Homework Equations Conservation of Momentum m1v1 + m2v2 = m1vo1 + m2vo2 The...

English isn't my main language, so I apologize in advance if something is unclear. We are leaving air resistance out of this problem! 1. Homework Statement We are going to describe the force F from the trampoline on the Joe as F = kx, k is a spring constant. This is a model. 1. Joe drops...

Homework Statement Two blocks of mass 2M and M head toward each other sliding over a frictionless surface sliding with speeds 4v and 6v respectively. After the collision the 2m mass is at rest, and the mass M has a velocity of 2V to the right. Was the collision elastic or inelastic? a...

I was reading a book which had some comments on EPR paper (Einstein, Podolsky, Rosen - 1935) like following: In Newton's physics, when two identical billiard balls hit each other head-on, bouncing off in opposite direction, knowing one ball's position and speed will also indicate other ball's...

Homework Statement A boy launches a 20 g dart horizontally by a spring gun from a balcony 45 m above the ground. The dart lands 15 m away from the balcony. If the length of the gun’s barrel is 10 cm, what is the average horizontal force applied by the spring?(A) 1.0N (B) 2.0 N (C) 2.5 N (D) 5. N...

Okay, so I did an elastic collision with Vernier carts and magnets. The results seem pretty good. Cart one started with -0.1205 kg*m/s ended with +0.1027 kg*m/s Cart two started with +0.1174 kg*m/s ended with -0.1118 kg*m/s So Total before = -0.0031 kg m/s and total after = -0.0091 kg m/s. If...

So,this is problem from David Morin's Classical Mechanics(Screenshot 1). I solved the problem. Then I went to see the solution in manual hoping for out of box thinking. As in screenshot 2 is solution by Morin. My question is why he conserves angular momentum about the point (R-h) below C.M...

Homework Statement Homework Equations The conservation of momentum states that if there are no external forces acting on a system, then momentum is conserved (i.e., the momentum before an event is equal to the momentum after an event). (Note: We assume that the internal forces follow Newton's...

Statement of the problem : "Using the definition L = r ##\times## p, prove that the direction of L is constant for an alpha (##\alpha##) particle whose scattering is shown in the diagram below. " Relevant equations : We are aware that the scattering takes place via a central force F = F(r)...

So the classical law of force given by Newton is F= ma = dp/dt = qE. Thus if i integrate the last two equivalents I get: ∫(dp/dt)dt = q∫Edt p + C = q∫Edt correct? then what would the integral of...

Perhaps naively I assumed that for a relativistic particle the product of mass times velocity would be the same in both Newtonian and Einsteinian mechanics. The simplistic thinking was the mass increase in relativistic dynamics would balance out the non-real superluminal velocity of a particle...

Good day dear forum, greetings from Argentina. I am studying the Lamb Shift, which says that in the atomic orbitals, an upward energy shift occurs due to an interaction of the electron with itself. This means that a level s can have an energy slightly greater than a level p. So far so good, but...

Homework Statement A system has a ball and a uniform rod. The rod is rotating about point X on a frictionless table until it strikes the ball. The rod stops and the ball moves away. Variables: Rod's mass: m1 Ball's mass: m2 Rod's original angular velocity: ω Ball's final velocity: v Rod's...

<Moderator's note: Moved from a homework forum.> Mass (g) +/- 0.01 grams Drop height (centimeters) +/- 3.00 Shell 53.47 45 No crack 56.78 45 Cracked...

I apologize for the simplicity of the question. I have been reading a paper on the Legendre transform (https://arxiv.org/pdf/0806.1147.pdf), and I am not understanding a particular step in the discussion. In the paper, Equation 16, where ##\mathcal{H} = \sqrt{\vec{p}^2 + m^2} ##...

Statement of the problem : A ball shown in the figure is allowed to swing in a vertical plane like a simple pendulum. Answer the following : (a) Is the angular momentum of the ball conserved? No, the angular momentum ##L = mvl##, where m is the mass of the ball and v is its speed at an...

Homework Statement Two satellites in space collide inelastically. What happens to the kinetic energy and momentum? a. both are conserved b. KE conserved but momentum reduced c. KE reduced but momentum conserved d. both are reduced e. KE reduced but momentum increased Homework Equations elastic...