0 Members and 1 Guest are viewing this topic.

(i) By hiding √{1 - v^{2}} in the mass, we may forget it is there. ...(ii) One may get the mistaken impression that to go from classical to relativistic mechanics its only necessary to replay all masses by m_{R}. This certainly works for the momentum p = m_{R}v, but it does not work, for example, for kinetic energy: The relativistic kinetic energy is not (1/2)m_{R}v^{2}. And it works in Newton's second law F = ma only in the very special case where the force exerted on a particle is perpendicular to its velocity. In all other cases F != ma.(iii) Relativity fundamentally serves to correct our notions about time and space. That is, it is really the dynamical equations dealing with motion, like energy and momentum, that ought to be changed, and not the properties of individual particles, like mass.(iii) When relativity is cast in four-dimensional spacetime form, ...., the idea of relativistic mass is out of place and clumsy.

I came across a special relativity text which says A particle does not become heavier with increasing speed. Do you believe the author is correct? What would you expect would happen to the magnitude of the gravitational field if the source of the field was moving?

Authors who don't use and don't like the concept of relativistic mass make arguments such as the following which are from Appendix F in the text Special Relativity by T.M. Helliwell page 259. I'm going to paraphrase a bit to save myself some typing but the essence of what I'm quoting will not be changed. The author uses the symbol m_{R} to represent relativistic mass.Quote(i) By hiding √{1 - v^{2}} in the mass, we may forget it is there. ...(ii) One may get the mistaken impression that to go from classical to relativistic mechanics its only necessary to replay all masses by m_{R}. This certainly works for the momentum p = m_{R}v, but it does not work, for example, for kinetic energy: The relativistic kinetic energy is not (1/2)m_{R}v^{2}. And it works in Newton's second law F = ma only in the very special case where the force exerted on a particle is perpendicular to its velocity. In all other cases F != ma.(iii) Relativity fundamentally serves to correct our notions about time and space. That is, it is really the dynamical equations dealing with motion, like energy and momentum, that ought to be changed, and not the properties of individual particles, like mass.(iii) When relativity is cast in four-dimensional spacetime form, ...., the idea of relativistic mass is out of place and clumsy.Of course I have my own opinions about each item but first I'm curious as to what others think about these arguments, so therefore please let me know what you think of each one. I'd like to thank all of you for giving me your opinion on this.

Define heavier.

This is a very interesting post. Define heavier.

I came across a special relativity text which says A particle does not become heavier with increasing speed. Do you believe the author is correct?

What would you expect would happen to the magnitude of the gravitational field if the source of the field was moving?

Authors who don't use and don't like the concept of relativistic mass make arguments such as the following which are from Appendix F in the text Special Relativity by T.M. Helliwell page 259. I'm going to paraphrase a bit to save myself some typing but the essence of what I'm quoting will not be changed. The author uses the symbol m_{R} to represent relativistic mass.Quote(i) By hiding √{1 - v^{2}} in the mass, we may forget it is there. ...(ii) One may get the mistaken impression that to go from classical to relativistic mechanics its only necessary to replay all masses by m_{R}. This certainly works for the momentum p = m_{R}v, but it does not work, for example, for kinetic energy: The relativistic kinetic energy is not (1/2)m_{R}v^{2}. And it works in Newton's second law F = ma only in the very special case where the force exerted on a particle is perpendicular to its velocity. In all other cases F != ma.(iii) Relativity fundamentally serves to correct our notions about time and space. That is, it is really the dynamical equations dealing with motion, like energy and momentum, that ought to be changed, and not the properties of individual particles, like mass.(iii) When relativity is cast in four-dimensional spacetime form, ...., the idea of relativistic mass is out of place and clumsy.

I think it's wrong, on the particle there should be a greater force, proportional to the gamma factor. But maybe the author intended to refer to its mass and not to its weight (which kind of book is it? Is it a universitary text?)

Don't know, but is it really the same question as the particle's weight?

I agree with these three points and I would even add others, but I've already discussed about them in many other threads.

Kinetic energy; 1/2MV2, cannot reach or exceed 1/2MC2, since rest mass cannot move at the speed of light.

If we tried to induce a mass to approach the speed of light, we would need to add infinite energy, yet kinetic energy is only able to reach the low finite limit of 1/2MC2.

Relativistic mass accounts for the energy difference; E=MrC2, so energy conservation applies.

Is there a definite answer, when two particles are moving on parallel tracks at a velocity near c is there a greater gravitational attraction between them than when they are moving at a more modest velocity.My own humble opinion is that there is not.

No particle's inertial mass or gravitational mass does not increase with speed. The issue is when someone applies an absolute frame of reference of speed assuming that the force necessary to accelerate it 1mph faster gets harder and harder to do the closer you are to the speed of light. Velocity isn't absolute, it approaches light speed and the momentum approaches infinity. The issue is that F=ma considers acceleration with absolute frame of reference. The idea of relativistic mass is only necessary in order to make sense of relativity in absolute Newtonian terms. It does not exist as an actual phenomenon. The issue is the Newtonian conception of inertia breaks down.

No particle's inertial mass or gravitational mass does not increase with speed.

In the fall of 2015 CERN will begin colliding groups of 70 million lead hadrons at 287 tev, unpacking millions of quarks in each collision. Those quarks will be first accelerated at light speed, acquiring relativistic mass, becoming heavier strange quarks, the substance of a strange quark-gluon soup called a ‘strangelet‘. The strange liquid has the potential to become stable and start an ‘ice-9′ big-bang reaction. If that happens that effectively transforms the Earth into a pulsar.

The issue is when someone applies an absolute frame of reference of speed assuming that the force necessary to accelerate it 1mpfaster gets harder and harder to do the closer you are to the speed of light.

Velocity isn't absolute, it approaches light speed and the momentum approaches infinity. The issue is that F=ma considers acceleration with absolute frame of reference.

The idea of relativistic mass is only necessary in order to make sense of relativity in absolute Newtonian terms. It does not exist as an actual phenomenon. The issue is the Newtonian conception of inertia breaks down.

What you appearing to be talking about is a coordinate value for inertia. So that it only appears to change with a change in reference frame. Correct me if I am wrong. I think input from a particle accelerator engineer would be useful.

Quote from: jeffreyHWhat you appearing to be talking about is a coordinate value for inertia. So that it only appears to change with a change in reference frame. Correct me if I am wrong. I think input from a particle accelerator engineer would be useful.Increase in inertial mass is a fact that can be found in any text on accelerator physics. It's in the new text I bought recently.

Quote from: PmbPhy on 24/07/2016 00:26:34Quote from: jeffreyHWhat you appearing to be talking about is a coordinate value for inertia. So that it only appears to change with a change in reference frame. Correct me if I am wrong. I think input from a particle accelerator engineer would be useful.Increase in inertial mass is a fact that can be found in any text on accelerator physics. It's in the new text I bought recently.Frazier seems to have an alternate view.

Abstract: If a heavy object with rest mass M moves past you with a velocity comparable to the speed of light, you will be attracted gravitationally towards its path as though it had an increased mass. If the relativistic increase in active gravitational mass is measured by the transverse (and longitudinal) velocities which such a moving mass induces in test particles initially at rest near its path, then we find, with this definition, that M rel=γ(1+β^2)M. Therefore, in the ultrarelativistic limit, the active gravitational mass of a moving body, measured in this way, is not γM but is approximately 2γM.

The U.S. National Budget. On 1983, particle physicists proposed that the United States build a gigantic 85 kilometer circumference particle accelerator called the superconducting super collider, costing over 6 billion dollars. One reason for the enormous size and cost is the special relativistic increase in the inertia of a particle moving near the speed of light that makes it harder and harder to accelerate it to higher speeds.

The principle of relativity can also be applied to more complicated situations, such as the collision between two bodies, or the motion of a charged body in an electric field. In order for the outcomes of experiments like these to be independent of the inertial frame, the effective mass, or inertia, of a moving particle must increase. The relativistic increase of inertia is what prevents particles from being accelerated up to and beyond the speed of light, because the inertia of the particle increases without bound as it approaches c. This has been observed countless times in particle accelerators, and must be figured into all the engineering specifications and cost estimates for more powerful accelerators.

If you accelerate proton to really really high velocity,and hit it with other stationary proton,there will be created proton-antiproton pair:

BTW, kinetic energy in Special Relativity is not E.K.=1/2*m*v^2.....

E.K.=m0*c^2*gamma-m0*c^2where gamma=1/sqrt(1-v^2/c^2)Basically, subtract relativistic-mass from rest-mass, and multiply by c^2.

Although it is not practical to measure whether two passengers sitting side by side in a spaceship approaching c experience an increased gravitational attraction it is possible to observe a bundle of Quarks called a Proton at high speed in the LHC where we are told it losses its spherical shape and becomes more like a pancake.Is this due to increased gravity between its parts or is there another explanation ?

Quote from: jeffreyHWhat you appearing to be talking about is a coordinate value for inertia. So that it only appears to change with a change in reference frame. Correct me if I am wrong. I think input from a particle accelerator engineer would be useful.I don't know any particle accelerator engineers but I do have the book Was Einstein Right by Clifford M. Will. Will is a renown experimental physicist. His area of expertise is relativity. All that I'm doing in this post is responding to Jeff's remark about input from an engineer. I'm assuming that he's okay with an experimental physicist in relativity. But I'm not doing this to start a debate on relativistic mass. We've beat that horse silly in this forum and other forums and I'd have an anxiety attack if I had to see people repeating those same old arguments in this thread. That would be off-topic. It was my intention when I created this thread that we discuss relativistic mass and weight and who those people are that make those mistakes. That's all. On page 262 Clifford Will writesQuoteThe U.S. National Budget. On 1983, particle physicists proposed that the United States build a gigantic 85 kilometer circumference particle accelerator called the superconducting super collider, costing over 6 billion dollars. One reason for the enormous size and cost is the special relativistic increase in the inertia of a particle moving near the speed of light that makes it harder and harder to accelerate it to higher speeds.On page 273 Will says just about the same thing, i.e.QuoteThe principle of relativity can also be applied to more complicated situations, such as the collision between two bodies, or the motion of a charged body in an electric field. In order for the outcomes of experiments like these to be independent of the inertial frame, the effective mass, or inertia, of a moving particle must increase. The relativistic increase of inertia is what prevents particles from being accelerated up to and beyond the speed of light, because the inertia of the particle increases without bound as it approaches c. This has been observed countless times in particle accelerators, and must be figured into all the engineering specifications and cost estimates for more powerful accelerators.Think how difficult it would have been to explain that without invoking an increase in inertia.

I have an unfortunate tendency to act as the devils advocate and put forward unlikely scenarios just to see how thoroughly they will be demolished I know all abought Lorenz transforms and how weak gravity is and also about the word not being flat despite what I was taught at school about parabolic moving missiles.

Does a particle's weight increase with speed?No, because gravity moves at the speed of light.

I think this is why it is important to keep the concept of proper mass alive.