Momentum conservation Definition and 241 Threads

Hi, Lets suppose we have 2 point masses one fixed and imoveable the other rotateing in a perfect circle around the first imoveable one with constant speed. Regardless of vich force is keeping the rotating mass on its circular orbit. It may be a string or gravitational force or whatever...

Homework Statement a drum of mass M_{a} and radius a rotates freely with initial angular velocity ω_{a}(0). A second drum with mass M_{b} and radius b greater than b is mounted on the same axis and is at rest, although it is free to rotate. a thin layer of sand with mass M_{s} is distributed...

I have been studying momentum and began believing that I understood it, but I began thinking... Between two objects of the same mass, the first object will collide with another object (let's say the second object is not moving) and the momentum, in an isolated system, will be transferred...

Hi guys, I've been thinking on a problem for a while which really bothers me. I've been trying to mathematically solve the following problem: A train approaches the station at a velocity of V=50 m/s. Then a tennis ball is thrown with a velocity U=30 m/s, against the approaching train...

Hi all, I have a question about mass conservation and the way that I should apply it on my problem. Consider a NxN Mass Matrix, (lets assume 10x10 came from 1D 10 node bar element). I am going to modify this matrix so I add some different unknowns to all terms (100 terms) from Physics...

I had read in a book that the primary reason for the use of tail rotor in a helicopter is to counteract the rotation of the main body generated as a response to the rotation of the main rotor blades to keep angular momentum of the rotor-body system zero. Is it true that the rotation of main...

My question is... when a ball falls vertically on an inclined plane with a velocity [v][/0] and let it collide elastically with the incline plane...let the angle of inclination be 'β' ... Now, here we conserve the momentum of the ball in the direction of commomn normal of the two...

Hi, So I recently worked out a problem in my mechanics class about two people jumping off a frictionless railroad cart at speed u. The result is that the cart will move faster if they each jump off separately than it would have if they both jumped at the same time. I've been trying to...

I'm reading about the derivation of the lande' g-factor which comes about when one considers an electron moving about a nucleus which is put in an external magnetic field. This gives rise to a perturbative hamiltonian H = - (\vec \mu_s + \vec \mu_s) \cdot \vec B_{ext} = \frac{e}{2m}...

Homework Statement A marble with a mass of 2.0 grams moves to the left with a velocity of 2.0m/s when is collides with a 3.0 gram marble moving in the opposite direction with a velocity of 2.0 m/s. if the first marble has a velocity of 1.5m/s to the right after the collision determine the...

Homework Statement http://s359.photobucket.com/albums/oo40/jsmith613/?action=view&current=MomentumConservation.png Homework Equations The Attempt at a Solution Working out how momentum is consered in this situation,... I know that the mass of an alpha particle is 4*mass of...

If an object falls there are two ways to consider momentum conservation Way 1: The system involves just the object therefore the gravitational force is an EXTERNAL force so momentum is NOT conserved Way 2: The system involves object and earth. The increase in momentum of the object down...

Consider a point mass of mass m going with velocity v towards a point mass also of mass lying still. Now conservation of momentum allows any combinations og mass times velocities that add to the total momentum before the collision. So for instance ½mv + ½mv would be good. This is where the...

Momentum conservation? Consider a ball falling towards the earth. I understand here how momentum is conserved here (ball momentum increases in one direction and Earth momentum increases in the other). BUT when the ball collides with the floor and it changes direction its momentum change is...

explanation for "Incompatibility with special relativity and momentum conservation"? Can anyone provide an explanation for this claimed contradiction between basic electromagnetism and momentum conservation? (Sorry, as a new member I can't post links.) News article: "Textbook...

Heat or deformation cannot contribute to velocity here, as per the view of conservation on momentum. So how is it that momentum is conserved but kinetic energy is not given a perfectly inelastic collision? The two masses stick together. There is no intrinsic means of expressing lost due to...

Homework Statement A teacher demonstates the conservation of momentum using a collision between a moving an a stationary trolley. Both trolleys stick together AFTER the collision. She measures the velocities using a motion sensor and data logger. Explain why the velcoties before and after the...

Work out in detail the situation in which a moving all collides with a stationary ball in a totally elastic collision. Assume the balls have the same mass when doing this calculation. How does conservation of momentum show itself in this situation? p = mv F = ma p1i + p2i = p1f +...

Homework Statement a mass M , attached to a horizontal spring executes SHM(simple harmonic motion) with amplitude A1 . when the mass M passes through its mean position then a smaller mass m is placed over it and both of them move together with amplitude A2 . the ratio A1/A2 is ...

I need the concept of momentum conservation in isolated systems described (in layman's terms,) as it pertains to the recoil of firearms, as described on this page. Bsharp.org : The Physics of Everyday Stuff : Gun Recoil I assume I am understanding it wrong, thinking he is saying that "while...

In optical parametric conversion process, such as second harmonic generation,the conversion efficient is determined by function sinc(ΔkL),where L is the length of the crystal,and Δk is the phase mismatch condition. When the sum of wave vectors of the two fundamental photon,equals to that of the...

A ball A (mass ma) with initial velocity v colides with a ball B (mb) initially stopped. A and B gets the same direction/velocity v', Calculate v' By linear momentum conservation ma.v = (ma + mb).v' v' = mav(ma + mb) But by mecanical energy conservation ma.v²/2 = (ma +...

If linear momentum conservation is instantaneous in real time, then angular momentum conservation must be too. In other words, if you want to get something spinning, then you must physically turn something else in the opposite direction. Angular momentum conservation can't be implied, it has to...

Homework Statement two identical bodies are sliding toward each other on a frictionless surface. One moves at 1 m/s and the other at 2 m/s. They collide and stick. The magnitude of the velocity of the combined mass is A. 3/4 m/s. B. 2/3 m/s. C. 1/6 m/s. D. 1/2 m/s. E. 1.5 m/s. F...

I have been studying spin, angular momentum, etc. And became curious about how relativity would affect a classical problem: eg: that of a mass rotating around a center of mass; In the classical case; two point masses of the same value, are separated by a distance 2r (mass-less attachement rod)...

Homework Statement I am having trouble with part B of this problem N people, each of mass mp, stand on a railway flatcar of mass mc. They jump off of one end of the flatcar with velocity u relative to the car. The car rolls in the opposite direction without friction. (a) What is the final...

Homework Statement Hi there. I have some doubts about an example I've found on the Ingard book of mechanics, matter and waves. It says: It is given to a homogeneous cylinder a horizontal speed V1 and an angular speed in opposed sense to that of the needles of the clock \omega_1=\frac{V_1}{R}...

Homework Statement You have a 99 kg mass and are stranded away from your ship, at rest, next to a giant 1800 kg ball of space doody. You push on the doody giving it a speed of 0.11 m/s directly away from the ship. Seven-and-a-half seconds later you come into contact with your ship. What was...

Homework Statement http://s861.photobucket.com/albums/ab174/alkaline262/?action=view&current=momentum.jpg why is it + w instead of -w, it seems like it sould be negative because the recoil velocity is in the negative x direction you have to admit that is a ms paint masterpiece :D...

I was thinking about internal torques and why they cancel, and I can't figure out how torques from magnetic forces cancel. Say you have two point charges moving with nonparallel velocities. The magnetic forces they exert on each other are opposite and equal, but they aren't along the line...

Homework Statement A ball of clay is thrown against a wall and sticks there. In this process, momentum is not conserved because the clay stops moving. The Attempt at a Solution Im thinking it's not because there is no velocity anymore for the clay? Is this right?

Homework Statement In the figure, a small particle of mass m = 25 grams moving at speed of v0 = 12 m/s sticks to the edge of a disk of mass M = 500 grams and radius = 11 cm. The disk then rotates freely about its axis as a result of the collision. (The disk is on an axle.) Find the angular...

Homework Statement Set the speed of light c=1. A particle of rest mass m_{0} decays at rest into a photon and loses rest mass \delta in the bargain. Show that the photon energy is \omega=\delta(1- \frac{\delta}{2m_{0}}) in the particle's rest frame before the decay. Homework Equations...

Note: this is one of the suggested practice problems for my second-year classical mechanics course. Homework Statement A spherical asteroid of mass m_{0} and radius R, initially moving at speed v_{0}, encounters a stationary cloud of dust. As the asteroid moves through the cloud, it collects...

I have been trying to research this and my understanding seems to be flawed. From what I have gathered from light sails and other sources: 1) The frequency of reflected light is the same as the incident light. 2 ) The photon imparts a kick to the reflected surface, Transfers momentum...

Homework Statement A wagon with mass M can move on frictionless surface. A mathematical/ideal pendulum is fastened on the wagon. At the initial moment the wagon and the pendulum were at rest and the pendulum makes an angle of x with the vertical. What will be the velocity of the wagon when the...

Second attempt here to get an answer, I am really lost on this. Im reading "A first course in String Theory" by Zwiebach and it says that when applying a general \tau gauge parametrization in the form of n_\mu X^\mu = \lambda \tau we can take the vector n_\mu so that for open strings...

Im reading "A first course in String Theory" by Zwiebach and it says that when applying a gauge parametrization in the form of n_\mu X^\mu = \lambda \tau we can take the vector n_\mu so that for open strings connected to branes (fixed end points), n^\mu \mathcal{P}^\tau _\mu is conserved...

We were told to make our own project, i chose to base mine on the conservation of momentum and used the pendulum. Though I am kind of stuck, i need more things to write about and more equations i can calculate using the pedulum. all i have so far is E=mgh H1=0.145m (90dgrs) M=0.045kg...

Homework Statement A binary star consists of two stars that are orbiting a common centre. The only force acting on the stars is the gravitational force of attraction in a direction along the line joining the stars. a) Explain carefully why the total momentum of the binary is constant...

Homework Statement A 100 kg man and a 90 kg man are rounding a corner and collide. The heavier man is running, while the 90 kg man is walking. What happens to the momentum of the 100 kg man? Does it increase, decrease, stay the same, or "is conserved"? Homework Equations Change in...

hi in rigid body questions are there cases where i should use moment conservation and not angular moment conservation or the opposite? when would i use which?

Hello. I have a problem that is making me crazy. Consider the following collision A + B \rightarrow C which results in both particles (A and B) being destroyed and C being created. I know the rest mass of all particles. Also, in the lab system, B is stationary and A is moving toward...

Homework Statement A beetle with a mass of 30.0 g is initially at rest on the outer edge of a horizontal turntable that is also initially at rest. The turntable, which is free to rotate with no friction about an axis through its center, has a mass of 80.0 g and can be treated as a uniform...

Homework Statement A ball whose momentum is p strikes a wall and bounces off, The change in the balls momentum is: A- 0 B- P C- 2p D- p/2 E-Infinity Homework Equations The Attempt at a Solution It's simple question but I want to make sure if my answer is true. The change in...

can the percentage error for final total momentum be negative in an elastic collision? It doesn't have absolute value in the equation given and I get a negative number, p(final) - p(initial)/p(initial) x 100 though small -0.528

Consider a frictionless plane. A particle of known mass and velocity (say a lump of clay) strikes a uniform rod (for simplicity let the rod be stationary in the lab frame) and sticks to it somewhere other than at the rod's center of mass. I wish to describe the linear and angular velocity of the...

Perhaps this question is silly, but I don't entirely understand how elastic scattering of photons is even possible given that the directions of the incident/scattered photon differ. If there is a change in direction of the photons momentum, then there must be some momentum transferred to the...

Electromagnetic radiated fields have both E and H fields perpendicular to the wave vector k. Therefore in photons the electric and magnetic fields are also perpendicular to k. This means that when photons are absorbed by some electron, the Lorenz Force will be mostly perpendicular to the...

Dear Friends.., I have something to share ..rather know about the mechanism of the angular momentum conservation principle still better.. consider a spacecraft , far away in a gravity less outer space..the spacecraft contains a man and a wheel. intially the angular momentum of the entire system...