Momentum Definition and 1000 Threads

Homework Statement A uniform thin rod of length ##2l## and mass ##m## lies on a horizontal table. A horizontal impulse ##J## is given to the rod at one end. There is no friction. The total kinetic energy of the rod after impulse will be ? Homework Equations ##Jl=I\omega## ##J=mv_{cm}##...

I understand for linear momentum the measure of the dificulty to take a body to the rest. But when I do the next exercises, I find that it requires less force for one body compared to the other with same linear momentum. Can someone explain me what to understand in an intuitive way what to...

Homework Statement Three small, identical 0.70-kg pucks are attached to identical 0.50-m strings, tied together at a common center as shown in (Figure 1) . Pucks are whirled in circular motion at angular speed 3.0 s-1 What is the magnitude of the angular momentum of the system about the...

Hi, Apologies if this questions is really easy but it is something quite subtle which is annoying me. In my book of quantum physics it gives a wave function of definite momentum: ψ = Aeipx/ħ It goes on to say that since there is a momentum 'p' in the exponential then the momentum is known...

Homework Statement In the figure, a 0.400 kg ball is shot directly upward at initial speed 58.3 m/s. What is its angular momentum about P, 1.42 m horizontally from the launch point, when the ball is (a) at maximum height and (b) halfway back to the ground? What is the torque on the ball about P...

Homework Statement A disk with a rotational inertia of 8.38 kg·m2 rotates like a merry-go-round while undergoing a torque given by τ = (5.03 + 1.01t) N · m. At time t = 1.00 s, its angular momentum is 6.57 kg·m2/s. What is its angular momentum at t = 3.00 s? Homework Equations dL/dt= T...

Hello guys. So this is less about about the physics problem and more about the concepts behind it. I don't need help with any solution but I am framing my questions around the example given. So there are two steel balls with equal mass that are hanging from a point by a string. Both strings are...

It explains very well many aspects of the Universe. Why should there be any angular momentum though? The idea that the Universe is itself intrisically rotating doesn't make sense.

Good evening, Does anybody know how to get the units of momentum flux? Momentum = kg m s−1 Flux = m−2 s−1 Somehow, I should end up with kg m-1 s-1 (kg m s−1) m−2 s−1 = kg m−1 s−1 However I end up with kg m-2 s-2 Is there anybody that knows what I'm doing wrong? :)

Homework Statement A rocket, weighing 43,600N, has an engine that provides an upward force of 120,000N. It reaches a maximum speed of 860 m/s. For how much time must the engine burn during launch in order to reach this speed? Homework Equations p=m*Δv i=F*t The Attempt at a Solution I started...

Homework Statement Three freight cars of equal mass are coupled together. The freight cars are traveling at 6.7m/s down a straight track when they collide with two more stationary identical cars. If all five cars are coupled together after the collision, then what is their speed if they are on...

I need help with an equation for the angle of the legs of a swing. I am building a swing. It is only 4 feet high, it is an indoor apartment swing for my son. I would like to know what the minimum legs angle would need be to support swinging 25 pounds in a 180 (probably less) arch. And if I...

Homework Statement What is the Average Force between m1 and m2. Show all work. Note that the masses are both at rest, and begin to push off of each other in opposite directions. Their velocity is measured when they reach 20cms distance. (I calculated the velocity when they reached this point...

Hi there, I am doing a physics assignment. I had to use a program called tracker to simulate the movement of a puck. So I just need some help to see if anyone can figure out what I've done wrong as something isn't making much sense. Let's jump right into it. When the puck moves down and hits...

Why the tangential velocity of a particle increase if there are no external torque acting on it and its angular momentum is conserved? I know that L = I.ω (angular momentum equals moment of inertia times angular velocity) and v = ω.r (tangential velocity equals angular velocity times the...

Dear Members, I was going through some video lecture (Quantum Mechanics) when I encountered a definition of momentum as shown in the attached picture. I do not understand how iota and ħ is ignored ? There are some negligible terms after plus sign. What are those ? In short how they have...

Homework Statement A two-stage rocket is traveling at 4500 m/s before the stages separate. The 3000-kg first stage is pushed away from the second stage with an explosive charge, after which the first stage continues to travel in the same direction at a speed of 3000 m/s . How fast is the...

Homework Statement [/B] A rocket that starts at rest with mass M ejects exhaust at a given speed u. What is the mass of the rocket (including unused fuel) when its momentum is maximum? What is the mass when its energy is maximum? Homework Equations [/B] p = mv The Attempt at a Solution...

- This is the situation provided where it has to be demonstrated that linear momentum is not conserved or unrealistic. My assumptions are: there's no friction due to how Godzilla is moving, the sand is acting as a lubricant. Velocity is constant. This is an elastic collision. I also guess that...

Homework Statement A satellite is in a circular orbit passing over the North and South geographical poles as it orbits the Earth. It has a mass of 2200kg and its orbit height is 870km above the Earth's surface. What is the change in momentum of the satellite from when it passes over the...

Homework Statement There are two objects m and 2m and Force F is applied on both objects. They move a certain distance X. Which one have greater momentum and find out 2m has √2 times more momentum than m. Homework Equations momentum P=mv The Attempt at a Solution 2m has greater momentum...

Homework Statement We did a lab where we had one cart with an unknown mass stationary on a friction-less surface. Another cart with a mass of 378.9g, was pushed down the track (which moves at a constant speed due to the friction-free surface) and collides with the second cart - so it is a hit...

Given that position and momentum are Fourier conjugates, what is the derivation for the equation ##\hbar \vec{k} = m \vec{v}##, where momentum-space momentum is defined as ##\hbar \vec{k}## and position-space momentum is defined as ##m \vec{v}##?

γ+2D ----> 1H + 1n In this photonuclear reaction, is it possible to write the momentum balance equation as it follows, MHvH = Mnvn It somehow seems to wrong to me, since the incoming photon has a certain momentum, which is not taken account in the balance equation. Thank you in advance.

Homework Statement A rocket sled moves along a horizontal plane, and is retarded by a friction force friction = μW, where μ is constant and W is the weight of the sled. The sled’s initial mass is M, and its rocket engine expels mass at constant rate dM/dt ≡ γ; the expelled mass has constant...

Homework Statement want to find the direction and moment of this diagram. Homework Equations The Attempt at a Solution [/B] I really do not have any idea about this question. So If someone helps, It'd be great.

Homework Statement A projectile traveling vertically strikes a block and stays in it. The mass of the projectile is 0.20kg and its speed is 3.0m/s at the instant of impact. The mass of the block is 1.3kg. Air resistance may be neglected. (a) How high does the block rise? (b) How much kinetic...

1. Homework Equations [/B] P = mv The Attempt at a Solution [/B] VCos(30) + 0 = nCos(60) + 2Cos(20) VSin(30) + 0 = nSin(60) + 2Sin(20) where I let n = any speed, I'm not sure if my attempt at the solution is correct.

Homework Statement The luminosity of the star is defined as ##\phi = L/4\pi r^2## The photons from the star hits the sail of mass ##M## and cross sectional area ##A##. What's the final velocity of the sail after getting hit by photons for a small time t? Assume the collision is elastic and the...

A pet mouse sleeps near the eastern edge of a stationary, horizontal turntable that is supported by a frictionless, vertical axle through its center. The mouse wakes up and starts to walk north on the turntable. Is the momentum of the system constant? i understand that the initial momentum is...

Homework Statement it is given in the image i uploaded Homework Equations L→=r→ × p→[/B] The Attempt at a Solution If the angular momentum of a particle is the cross product of the position vector of the particle from the axis and its linear momentum, how can the angular momentum of m1 and...

There is something I don't quite understand about the law of conservation of angular momentum. Let's say a person is rotating about an axis passing through his/her centre of mass, with an angular speed speed ω1, and has a rotational inertia I1 about about the centre of mass. No torque is acting...

Homework Statement Assume two masses m1' and m2' are moving in the positive x-direction with velocities v1' and v2' as measured by an observer in S' before a collision. After the collision, the two masses stick together and move with velocity v' in S'. Show that if an observer in S' finds...

How true is this? Do you believe that in the double slit experiment, what is subsequently measured at the detection screen is actually the particle’s momentum?? How does this differ to the normal double slit explanation of the particle being deflected left or right of the slit, etc...

Homework Statement Say you're bowling and you roll the ball down the lane. The bowling ball has just knocked the first bowling pin forward and that pin's forward velocity is now much larger than the bowling ball's velocity before their impact. How can the pin travel forward faster than the ball...

Hi all, Yet another question: if the universe is finite, then linear momentum should be quantized (I assume in a similar manner to an infinite potential well since there are boundary conditions). My question is, then, if one computes a value for ##\Delta p## (momentum variance), is the variance...

1. Homework Statement ( This question is from the textbook of Introduction to Elementary Particle Physics, written by Griffiths, on the problem set of Chapter 3 ) Particle A (energy E) hits particle B (at rest), producing particles C1, C2, ...: A + B → C1 + C2 + ... + CN. Calculate the...

Hello, After Favre averaging the momentum equation for an inviscid flow, the following can be obtained: $$\frac{\partial}{\partial t} \left(\overline{\rho}\tilde{u}_i \right) + \frac{\partial}{\partial x_j}\left( \overline{\rho}\tilde{u}_i \tilde{u}_j \right) + \frac{\partial...

Homework Statement Sorry for another question so soon, I am not sure if there is a limit on how many I can ask. I try to keep it to a minimum but sometimes I can't figure it out on my own. Question: In a physics lab, 0.30 kg puck A, moving at 5.0 m/s [W], undergoes a collision with 0.40 kg...

Homework Statement An egg is being dropped onto a wooden block. The egg cracks after an impact. The velocity of the egg just before the impact is 5m s^-1. Give two suggestions and explain on how you would avoid the egg from cracking from the same height Homework Equations Momentum: F=ma...

Hello, Im creating a physics simulator and I am struggling to expand my collisions from 2D to 3D. In 2D the velocity only changes parallel to the line of center so I presume this is the same for 3D.I can get a Cartesian equation of line but I am not sure how to get the velocity component...

told so in another thread that two photons traveling in opposite directions "have mass". I understood the concept of centre of momentum, an inertial frame of reference and rest mass. My cynical reply wasn't conveyed and I got well thought out and accurate replies. the COM is an idealized point...

Homework Statement Given a horizontal rod (parallel to x axis) and two disks attached near its ends symmetrically. The rods and disks are perfectly balanced i.e. the disks have same mass and density. The system's center of mass is exactly at geometric center of the rod (since its balanced)...

Homework Statement Homework EquationsThe Attempt at a Solution The angular momentum of the upper particle is given as ## \vec L_u = m \vec r \times ( \vec \omega \times \vec r )= m[ \vec \omega r^2 - \vec r ( \vec r . \vec \omega )] = m[ r^2 \vec \omega - \omega r \cos \alpha \vec r ]##...

Recently I was searching the internet and books for the connection between conservation of angular momentum and conservation of rotational energy and found nothing. Let's say an ice skater rotates and draws the arms in - the rotation speeds up. The rotational energy must increase because the...

I am not sure if I am at the right place and I hope that I am... For my EE I want to do an investigation on something related to pool table and games so it will definitely be related to momentum. And one of the common techniques in pool games is that the player aims the ball on the rail of the...

Homework Statement Homework Equations Angular momentum = moment of inertia * angular velocity Change in angular momentum = impulsive moment v^2=u^2+2as The Attempt at a Solution First I used v^2=u^2+2as to find the velocity of the particle the moment the string goes taut. I got v=\sqrt{8ag}...

An assumption in deducing the Bethe equation is that the momentum transfer is perpendicular to the direction of the particle. ALSO In Allison & Cobb (1980), just after eq. 28, they state that the first two terms of the Photoabsorption Ionization model arise from the magnetic vector potential...

Homework Statement Given 2 magnets of equal weight (w0) and each with a magnetic strength (t0) placed inside a straight hollow cylindrical tube. One of the magnets is attached to one end of the tube and the other magnet is free to move inside the tube. The other end of the tube is open to...

I was doing some practice problems to become more familiar with the Center of Mass Velocity and I came across this one from (Noted in the picture) Engineering at Illinois, that relates the velocity of the center of mass in both the x and y direction, however I don't quit understand the answer...