Conservation of momentum Definition and 757 Threads

How do you account for the conservation of momentum for a photon? Specifically, if you have light traveling in a medium where the refractive index is not constant. For example, a graded index multi mode fiber optic. So here is another diagram to help articulate my question. Inside this graded...

Homework Statement Please see the attached photo. (down) Hminitial= 1.5R M = 2/3m Perfectly elastic collision What is the velocity of object m immidiatly after the collision? (by m,g,R) Homework Equations Conservation of energy Conservation of momentum The Attempt at a Solution I assumed...

Hi, Homework Statement A free falling object of mass "m" falling from some height, collides the floor in speed of 20 m/s (perfectly elastic collision). In his 1/2 height back up he splits into 2 pieces- ¼m which going downward and ¾m keeping upward. The ¼m reaching the floor after ½ second. 1)...

Hi everybody, I apologize if something like this has been asked before but I have been unable to find an answer through searching. If a weight is carefully added to a moving cart then the cart should slow down due to conservation of momentum. How is it that the cart has accelerated without a...

Homework Statement A uniform rigid scale is held horizontally with one of its end at the edge of the table and the other supported by hand. Some coins of negligible mass are kept on the meter scale. As the hand supporting the scale is removed, the scale starts rotating about its edge on the...

Homework Statement A 39.00 kg rod of length 2.8 m is hanging vertically by one of its ends that is free to swing in a complete circle about a frictionless axle/pivot. The rod has uniform mass density. Suddenly it is struck horizontally by a 5 kg putty that sticks to the center of...

Let's say you've got a boat filled with n frogs of mass m each. Let's also say that all the frogs jump simultaneously out of the boat in the same direction with velocity v, then the boat will get a velocity v1 in the opposite direction because of conservation of momentum. Now if we instead let...

Homework Statement The same horizontal force is applied separately to two objects initially at rest on a horizontal, frictionless surface. Object A has less mass than object B. In each case the force is applied for the same length of time. Which of the following statements is true after the...

Homework Statement its a nuclear physics problem : a deuterium atom with energy 4Mev collides with a boron atom B5/10 in an elastic collision producing an H1/1 and B5/11 ,the Q of the reaction = 9.23 Mev . find the E,E' , the energy of the boron and the hydrogen the unknowns : E,E', theta of...

I would like to check my understanding for this problem : A puck with mass ##3m## is stationary on a horizontal friction-less surface. It is being impacted in an elastic head-on collision by another puck with the mass ##2m## traveling with speed ##u## to the right. Find the speed and direction...

Homework Statement So for those who aren't familiar with the Gauss Gun here is a video demonstrating its function: As you can see in the video, a steel ball is rolled towards a sequence of magnets and other steel balls and as the incoming ball strikes the magnet, the ball on the other end...

Homework Statement Let two particles of equal mass m collide. Particle 1 has initial velocity v, directed to the right, and particle 2 is initially stationary. A: If the collision is elastic, what are the final velocities v_1 and v_2 of particles 1 and 2? B: Now assume that the mass of...

Homework Statement [/B] The problem is as follows: in a reference frame there is one electron at rest and one incoming positron which annihilates with the electron. The positron energy is E and two gamma rays are produced. Find first the energy of the photons in the center of mass frame as...

In classical field theory, translational (in space and time) symmetry leads the derivation of the energy-momentum tensor using Noether's theorem. From this it is possible to derive four conserved charges. The first turns out to be the Hamiltonian, and thus we have energy conservation. The...

Homework Statement Show that if an elastic collision between a mass and a stationary target of equal mass is not head-on that the projectile and target final velocities are perpendicular. (Hint: Square the conservation of momentum equation, using ##p^2=p\cdot p##, and compare the resulting...

Homework Statement So basically I have a train with two joined carriages which become separated (m1) Mass one =13563kg and (m2) Mass two =30394kg. the initial velocity of the joined carriages is 5.00m/s (u1). When the carriages separate I have the final velocity of (m2) which is 0.96m/s (v2)...

Homework Statement I am investigating a scenario where a pendulum with a bob attached is released from an angle and pushes a box to a certain distance. My goal is to find the coefficient of friction between the box and the surface it moved on. I have measurements for: - mass of the bob (125...

Homework Statement Playing in the street, a child accidentally tosses a ball (mass m) with a speed of v=23 m/s toward the front of a car (mass M) that is moving directly toward him with a speed of V=20 m/s . Treat this collision as a 1-dimensional elastic collision. After the collision, the...

Homework Statement A spaceship of frontal area 25 m2 passes through a cloud of interstellar dust at a speed of 1.0x106 m/s. The density of dust is 2.0x10-18 kg/m3. If all the particles of dust that impact on the spaceship stick to it, find the average decelerating force that the impact of the...

Note: Please only give hints please! No answers because I want the satisfaction of solving it. 1. Homework Statement A mass M at height h above flat round and falling vertically with velocity v breaks up explosively into 2 parts. The kinetic energy given to the system in the explosion is E...

When an RF antenna absorbs a signal, the momentum is transferred in quantized photon-electron interactions. The electrons in the metal will be given both perpendicular momentum (the actual signal information) and momentum in the direction of propagation (shown below): The momentum in the...

I rarely hear about momentum entanglement, do you know any experiments/applications for momentum entanglement? If we do momentum entanglement on 2 particles, and then we accelerate one of the particles, will the other particle slow down to obey conservation of momentum? or entanglement will be...

Hi all, I have a little problem while reading Feynman lecture note volume 2, chapter 40, section 40-3. In that section Mr Feynman talked about Bernoulli equation and a example of a filled water container. In high school we learned that if we drill a hole near bottom of container, we can get...

Homework Statement A block of mass 200g is suspended through a vertical spring. The spring is stretched by 1.0 cm when the block is in equilibrium. A particle of mass 120g is dropped on the block from a height of 45 cm. The particle sticks to the block after the impact. Find the maximum...

If we consider a cart of mass M ,moving along a friction-less track, with velocity v on which a boy of mass m, stands at rest initially at the front end of the cart . If the boy jumps from the cart, in the direction of motion of the cart with a velocity u relative to the cart, what will be the...

In a classic problem where a man walks along the length of a boat floating on the surface of water without friction, Should the net work done due to static friction between the man and the boat be zero. If the length of the boat is L, its mass being M, and the mass of the man being m, the...

Homework Statement I am happy to re-write the question, but I'm just leisurely working through a list of problems I found online, so here is the link (with picture). http://web.mit.edu/2.25/www/5_pdf/5_01.pdf Homework Equations Cons of Momentum Cons of Mass The Attempt at a Solution a) I...

Homework Statement A super cue ball is made of the same material with the target ball (radius r) but slightly larger: rc = (3)^(1/3)*r The cue ball collides with the target ball on a frictionless table, as shown below, with initial speed of v0. The collision is not head-on, as shown below. a)...

I have a ball and the wind blows on it. Could I find the initial velocity of the ball from conservation of momentum? m_air * v_air = m_ball * v_ball v_ball = (m_air * v_air) / m_ball What would you put for m_air?

Homework Statement A rocket is fired from from the ground at initial velocity of ##v_0## and at an angle ##\theta##. At its highest height it splits into 2 parts of equal masses. The first part is fired straight up and at velocity ##v_0/2##. Find the angle and intensity of the second part...

Homework Statement (This is a problem I myself created, so it may sound a bit trivial/stupid.) A particle of mass m in the xy plane has velocity v and a radius vector r with respect to some origin. After some time Δt, the same particle has velocity v and a radius vector r' with respect to the...

Is the law of conservation of momentum valid in non isolated system . What is an isolated system? My teacher confuses me that the law is valid in an non isolated system . They even say that when we say about the isolated system (meaning they are present ) we do not consider the air resistance...

Question says" When a car comes to a normal stop its momentum is not conserved. Does this violate the principle of conservation of momentum? Explain. What happens to the car's kinetic energy?" My question is why momentum is not conserved when a car comes to a normal stop?

For my senior design project, my group is tasked with creating a wind turbine. At the moment, I am trying to figure out what approximate RPM the blades will rotate at so we can select an appropriate gear ratio and generator. Our advisor instructed us to use conservation of momentum on the...

A particle of mass 3kg moving at 15ms^−1 collides with one of mass 2 kg moving at 5ms^−1 in the same direction. Calculate the velocities after the collision i. the collision is elastic. ii. Suppose that in the collision of part (i), the final velocities are not parallel to the initial...

Homework Statement A spherical satellite of radius r is moving with velocity v through a uniform tenuous atmosphere of density ρ. Find the retarding force on the satellite if each particle which strikes it (a) adheres to the surface and (b) bounces off it elastically. I know the answer should...

Homework Statement So during collisions between 2 point masses, I know that momentum is always conserved, but energy may or may not be conserved. Now, in this case, where we have a block colliding with a pivoted rod, I know that angular momentum is always conserved, but neither energy or...

Homework Statement Will momentum not be conserved in the case of a free fall because gravity is considered an external force? Is this because the system is not isolated? If this is the case, I understand the concept now, but could someone give me another example of an external force that will...

Homework Statement Homework Equations Conservation of liner and angular momentum H1=H2 r x M1V1= r x M2V2 G1=G2 M1V1=M2V2 The Attempt at a Solution I've gotten an equation for the velocity of the block and clay after the impact, and I also know that when the block reaches the highest point...

Homework Statement Block A (of mass MA) rests on a frictionless horizontal table. It is connected via a light string to block B (of mass MB) hanging over the edge of the table. The pulley itself, a solid disc, has non-negligible mass MC. The light string does not slip over the pulley. What is...

Homework Statement I am studying for an upcoming exam and stumbled upon a website with a bunch of practice problems. I would typically state the question but this one is so long and requires a picture so here is the hyperlink to it: http://web.mit.edu/2.25/www/5_10/5_10.html Homework Equations...

When we use the conservation of momentum with, for example, collisions do we include the sign with the velocities or are the signs inherent in the quantity? For examples, would we write ##m_1v_1 = m_1v_1 + m_2v_2## or ##m_1v_1 = -m_1v_1 + m_2v_2## for a collision where a moving object hits a...

When reading lessons on the conservation of momentum, you usually see examples with colliding balls or something to that effect. These examples always seem to fail to mention friction. These balls will always come to a stop due to friction. How is momentum conserved when it is lost to friction...

The problem statement Example 1 A single particle I have a particle being forced by a radial centripetal force onto a smaller radius $$l_1=m_c.v_1.r_1$$ $$L_1=L_2$$ $$L_2=m_c.v_2.r_2$$ $$m_c.v_1.r_1=m_c.v_2.r_2$$ $$v_1.r_1=v_2.r_2$$ $$v_2=v_1\frac{r_2}{r_1}$$ Its increase from ##v_1## to...

I have been reading many examples of control volume calculations regarding nozzles They all end up with a reaction force on the nozzle in the direction of the flow. I can't understand this from a Conservation of momentum perspective. I would expect that the reaction force, by Newtons third...

Homework Statement An 8.0-kg object is sliding across the ice at 2.34 m/s in the positive x direction. An internal explosion occurs, splitting the object into two equal chunks and adding 16 J of kinetic energy to system. The explosive separation takes place over a 0.16-s time interval. Assume...

Homework Statement Show that the largest possible change in the kinetic energy , ##\Delta E_{kin}##, of a particle of mass ##m## running into another particle of mass ##M## at rest in the lab coordinate system is \Delta E_{kin} = \frac{-4AE_{kin}}{(1+A)^{2}}, where ##A = \frac{M}{m}##...

Hi I have been dealing with a fluid mechanics pressure gradient problem and from a statistical view point I can see how it resolves itself but am puzzled as to how it can occur at the molecular scale from a conservation of linear momentum perspective if Momentum is a conserved quantity While...

Homework Statement An incompressible fluid of density ##\rho## flows steadily through a 2D infinite row of fixed shapes. The vertical distance between shapes is ##a##. Define station 1 as the space where velocity enters and station 2 where it exits. Also, velocity and pressure are constant...

So I read that the conservation of momentum is a result of: F1=-F2 <Newton's Third Law t1=t2 <Time in contact Therefore: F1*t1=-F2*t2 F=m(Δv/t) Ft=mΔv So we can conclude: m1Δv1=-m2Δv2 Therefore momentum is conserved. Now what force is this? Would it be the same normal force that exists when...