Relativistic momentum Definition and 105 Threads

When accelerating an electron through a PD of 10^3, that will give a momentum of 1 MeV/c right? Or is there something I'm not taking into account with relativity? Thanks :D

Hi everyone, I found a derivation for relativistic momentum on this page: http://en.wikibooks.org/wiki/Special_Relativity/Dynamics I understand it all the way through, except the point where they have come to this equation. m_{red} = \frac{m_{blue}}{\sqrt{1-(\frac{u(x,r)}{c})^{2}}} Where(as...

Homework Statement show the d(γmu) = m(1-(u^2/c^2))^(-3/2) Homework Equations C = constant, m = constant, γ= (1-(u^2/c^2))^(-1/2) The Attempt at a Solution So in calculating d(γmu)/du, I thought I would take out the m first since it is a constant and then just add it in later...

Homework Statement Find the force necessary to give a proton an acceleration of 10^19m/s^2 when the proton has a velocity ( along the same direction as the force) of 0.9c Homework Equations p=gamma * m * U F = d/dt [gamma * M * U] F=gamma^3 *m*a The Attempt at a Solution initial momentum...

The relativistic momentum is given by p=mvγ, where Y is the Lorentz factor and m is the rest mass of the body. My question is that if we are considering the momentum of the body at relativistic speeds, shouldn't we also consider the relativistic mass of the body?

Hi everyone. So basically I am still struggling to find a description of the derivation of relativistic momentum (via relativistic mass) which explains itself properly (although that may be my fault for not understanding). So, I tried doing it with help from Feynman and can't work out what I'm...

Derivation of Relativistic Momentum WITHOUT using Relativistic Mass? Does anyone know a way to derive relativistic momentum without falling back on the concept of relativistic mass? Also, if it is not already part of the derivation given, does anyone know how to show that relativistic...

Hi, so basically have been looking at http://en.wikibooks.org/wiki/Special_Relativity:_Dynamics#Momentum" and working my way through the maths for myself. However I have hit this point and can't get past it: \begin{align} u = \frac{v - u}{1-\frac{uv}{c^2}} \end{align} Which should be...

For the relativistic momentum p=(1/[1-u^2/c^2])mv does u always equal v or does u refer to the speed of the reference frame and v refer to the speed of the object?

Relativistic momentum is a vector, just as non-relativistic momentum is a vector, right? Part of the relativistic energy equation includes relativistic momentum. See here please: http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/releng.html" Could the relativistic momentum energy part of...

Let's say that according to frame B, we have two identical bodies with the same invariant mass, say 1 kg, each traveling in opposite directions at .1 c, where v1 = .1 c and v2 = -.1 c, which then collide and stick together. Since the frame is homogeneous and the bodies are identical, they will...

I have in mind to build a game to help teach or demonstrate some concepts in QM and I thought it would be nice to be able to measure momentum. So as a proof of concept before I get too many man hours burned on the project I thought it would be good to do the infinite square well. I managed to...

In a practice exam I just did for my upcoming high school mid-year, there was a multiple choice question and the two answers that seemed plausable were "relativistic momentum depends on the mass and velocity of the object" or "relativistic momentum depends only on the mass of the object". I...

Last week in physics we were learning about special relativity and we got the equation p=λmv. When writing the equation the teacher also put the equations for regular momentum p=mv and regular force F=ma. I noticed that momentum is the integral of force where v is the integral of a and mass is...

Homework Statement A particle of unknown mass M decays into two particles of known masses m1 = 0.5 GeV/c2 and m2 = 1.0 GeV/c2, whose momenta are measured to be p1 = 2.0 GeV/c along the positive y-axis and p2 = 1.5 GeV/c along the positive x-axis. Find the unknown mass M and its speed...

Homework Statement What is the speed of an electron (me=0.511 MeV/c2) with a momentum p=5 MeV/c. Homework Equations Starting with momentum: p=\gamma mu Then solving for u: u=\pm\frac{cp}{\sqrt{c^2m^2+p^2}} The Attempt at a Solution I've never dealt with these units before (MeV/c2 and...

I'm having some problems trying to figure out how to derive relativistic momentum. The way it was explained to me, classically, p=mv=m(dx/dt),but dx/dt is measured differently in different reference frames. So, if you look at time dilation, t=ɣt' where ɣ= 1/(1-(v/c)^2)^1/2 and t' is time in the...

Homework Statement I need help rearranging the relativistic momentum equation in terms of velocity. Homework Equations p = (mv)/sqrt(1-((v^2)/(c^2))) The Attempt at a Solution p = (mv)/sqrt(1-((v^2)/(c^2))) p(sqrt(1-((v^2)/(c^2)))) = mv sqrt(1-((v^2)/(c^2))) = mv/p...

Homework Statement How fast must a body be traveling if its forrect relativistic momentum is 1% greater than the classical momentum Homework Equations P_r = mv/sqrt(1-(v^2/c^2)) P_nr = mv p_r = 1.01P_nr The Attempt at a Solution mv/sqrt(1-(v^2/c^2)) = 1.01mv mv =...

Homework Statement A gamma ray photon with wavelength=2.0 * 10^-15m is traveling in the positive x direction undergoes a one dimensional collision with a stationary proton. a.) find the relativistic momentum and energy of the photon and proton before the collision. b.) assuming the...

Homework Statement What is the most general mathematical form for the relativistic momentum which will prevent the velocity of an object from becoming greater than c, when the object is acted on by a constant force F and the equation of motion is dp/dt=F Homework Equations The...

Homework Statement A photon of momentum P strikes a nucleus at rest and s absorbed. If The final (excited) nucleus is M calculate its velocity. Homework Equations p = mv/(gamma) The Attempt at a SolutionP = Mv/gamma P^2 - (Pv/c)^2 = (M^2)(v^2) P^2 = (Mv)^2 + (Pv/c)^2 V = P / sqrt(...

Hi. I was wondering if anyone has a simple derivation of relativistic momentum from lorentz transformation or the relativistic velocity addition formulas. I have attempted to understand this example: http://en.wikibooks.org/wiki/Special_Relativity/Dynamics#Momentum but I have been having...

This is NOT homework (school is out), but it has the form of a problem because making up problems is how I "test" these ideas to convince myself they work. I tried the search function and couldn't find what I was looking for. EDIT- I am not trying to "show my own theory," etc. When I have been...

Homework Statement A meson (elementary particle) decays into two photons, each of energy 150MeV in its rest frame. Find the mesonic kinetic energy in the case of a symmetric decay in flight with an angle of 60degrees between the photon momenta (30 degrees for each particle on each side of the...

Homework Statement Unstable, subatomic particles called muons have a rest energy of 105.7 MeV and a speed of 0.994c. If a muon were to decay and produce an electron and a photon, what would be the momentum of the electron as measured by an observer in the muon's frame? HINT: assume that the...

Homework Statement A particle of mass m and momentum of magnitude 2mc strikes a particle of mass m, which is at rest. The two particles stick together after collision. c represents the speed of light. (a) Before the collision, the ratio of the speed of the moving particle to the speed of...

Homework Statement A particle of mass m(naught) moves throught the lab at .6c. Suddenly it explodes into two fragments. Fragment 1 has mass .66m(naught) and moves at .8c in the same direction as the original particle had been moving. Determine the velocity (magnitude and direction) and mass of...

Homework Statement Newton's Second Law is given by F=dp/dt. If the force is always parallel to the velocity, show that F=y3ma

Homework Statement In a certain reference frame, a particle with momentum of 7 MeV/c and a total energy of 9 MeV. Determine the mass of the particle. I did not mistype this problem, this is the way it appears on my assignment. Homework Equations Total Relativistic Energy...

Hello everyonea. I was studying special relativity and i got stuck on an example. Here it is:'to an observer,two bodies of equal rest mass collide head on with equal but opposite velocities 0.8c and cohere. To a second observer,one body is initially at rest. Find the apparent velocity of the...

Homework Statement A woman is 2.0 m tall and has a mass of 60 kg. She moves past an observer with the direction of the motion parallel to her height. The observer measures her relativistic momentum to have a magnitude of 2.30x1010 kg·m/s. What does the observer measure for her height?Homework...

Homework Statement A football player with a mass of 82.1 kg and a speed of 2.00 m/s collides head-on with a player from the opposing team whose mass is 126 kg. The players stick together and are at rest after the collision. Calculate the speed of the second player, assuming the speed of...

Dear Friends Two identical particles are running, in opposite directions, along the x-axis of a reference frame having the origin coinciding with their barycentre; they hits frontally and glue together. Their speeds are ("b" for before collision, "a" for after) : V1b = u V2b = -u Va =...

Did I understand correctly that relativistic momentum is p(t) = m\cdot\gamma(t)\cdot v(t), where \gamma = c/\sqrt{c^2-v^2} and c is the speed of light? For the fun of it I wrote down the time derivative and got {d\over dt}p(t) = \gamma^3(t)\cdot a(t) with a(t) = d v(t)/dt. Yet I...

I have a question about photons and relativistic momentum. According to my Physics text (Serway & Beichner), the energy of a partle with zero mass, such as a photon, can be related by E^{}2=p^{}2c^{}2+(mc^{}2)^{}2. m=0 so the expression becomes E=pc. Since relativistic momentum is...

How does one take the time derivative of ϒmv ? I tried treating gamma and mv as separate functions but it just gets messy and ultimately wrong.

[SOLVED] Force using relativistic momentum I have an example problem in a textbook I'm reading: "Find the acceleration of a particle of mass m and velocity v when it is acted upon by the constant force F, where F is parallel to v. then it proceeds to show the solution: F =...

I was working a problem in a Modern Physics book: Find the momentum (in MeV/c) of an electron whose speed is 0.600c. My first approach was: mass of electron = 9.1E-31 kg \sqrt{1 - \frac{(0.600c)^{2}}{c^{2}}} = 0.800 p = \frac{9.1E-31 * 0.600c}{0.800} = 2.04E-22 (ignoring units)...

[SOLVED] relativistic momentum Homework Statement a particle with mass M and v=0 decomposes to a massless particle and another particle with the mass Q. find the momentum of the Q particle Homework Equations E^2_{cm}=m^2c^4=(\sum{E})^2-(\sum{P})^2c^2 The Attempt at a Solution i...

Homework Statement A particle with mass m and speed (4/5)c collides with a particle (with mass m as well, but speed = 0) un-elastically, and continues as one particle. I have to find the speed and mass for this "joined" particle. The Attempt at a Solution Ok, first - conservation of...

Homework Statement A Lambda0 (L0) hyperon at rest decays into a neutron and what? (a) Find the total kinetic energy of the decay products. (b) What fraction of the total kinetic energy is carried off by each particle? I have both the decay process and the total kinetic energy. L0 -> n+ p°...

Many books teaching relativity at the introductory level,go on and say that relativistic momentum can't be described using p=mv and p=m Dx/Dt(D is Delta) also it says the measure Dx is the same as measured by the both people.One who is measuring his own momentum and another who is...

I asked a quite similar question about relativistic mass and the reason for this question is identical: I can't seem to dig up any derivation for the equation for relativistic momentum: p=\gamma mv If anyone could point me in the right direction, I'd much appreciate it.

Homework Statement At what speed is the magnitude of the relativistic momentum of a particle 11 times the magnitude of the nonrelativistic momentum? Homework Equations P=mv/(1-v^2/c^2)^1/2 The Attempt at a Solution 11=v/(1-v^2/c^2)^1/2?

Homework Statement Would someone teach me how to do: \frac{\bold dp}{\bold dt} I am deducing for myself all relativity, but I don't know how to do this now. It is not homework, it's self teaching. Thanks in advance. :smile:

Explain using 4-momenta, how if a particle of mass M decays into photons, it must decay into two or more photons. Does your explanation still hold if the particle is moving at high speeds while it decays? I can see if the particle is at rest and decays how it would have to decay into two or...

many textbooks start teaching relativistic dynamics by defining the relativistic momentum as p=dx/dtau dtau representing a proper time interval. an alert student could ask why? how would you answer?

I am having trouble with getting the right answer for this problem that is pretty simple and it is driving me insane. You start out with a pion that decays into 2 photons that split at an angle theta in opposite directions from the original pion. The velocity v of the pion is 2.977*10^8 m/s...

1. Why do we have to assume mass doesn't change? And always use m_0? 2. OK, let's assume we always use m_0. Then why is momentum is defined as \frac{mv}{\sqrt{1-\frac{v^2}{c^2}}}. If measuring in object's frame of reference, shouldn't we use his distance and time, where they are...