Relativistic mass Definition and 116 Threads

I've been thinking of something for quite a while I'd would really appricate some opinions of the matter. I was wondering if the mass density of an object changes when it approaches the speed of light, just like charge density changes and causes the lorentz force. Could this change in mass...

As a mass approaces the speed of light it's inertial mass in the direction of motion increases. But what about it's intertial mass perpendicular to the direction of motion? Does it also increase? And finally, what about the gravitational field "produced" by the mass. Has it increased as well?

I've a question here, is there a way to derive m'= \gamma m ? So far, i have not seen any derivation to this. I have heard that relativistic mass is a definition, but how did Einstein thought of this?

well, I'm very new to this, but I'm interested in learning. recently i followed a link from these forums that lead me here http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html which states: well, I'm a little confused now, because if energy and relativistic mass are...

how to differentiate between the two masses in equation for relativistic mass? m= mo/sqroot 1-v^2/c^2 what's the difference between m and mo? and what about for energy: eo and e?

I know this question was covered here in the past, but I got some mixed answers. I hope somebody can clear this up for me.

what is the relativistic mass of a single photon

From what i heard, my friend told me relatvistic mass has just been recently proven wrong. Is that right?

Suppose that nothing in the universe existed, except for one solitary billiard ball. For the sake of definiteness, let it be an eight ball. So the center of mass of the universe is the center of mass of the eightball. Now, the eight ball has an inerital mass m, which is either a function of...

I had some trouble with this question, but I would like to know if for these type of questions, is it safe to say that the velocity of a particle/object is equal to: v=\sqrt{\mid\frac{{m_0}^2}{{X_{m_0}}^2}-1\mid c^2 Where X is equal to how many times larger it's relativistic mass is...

Could someone check my solution and ensure I did this right? I am pretty sure it is... but this whole relativity thing is new to me and I want to make sure I didnt screw something up somwhere. :biggrin: The question is: What is the speed of an objects whose mass is three times its rest...

In another thread dextercioby posted the http://https://www.physicsforums.com/showpost.php?p=406225&postcount=13 I want to address this interesting comment here so as not to divert the other thread. dextercioby - What's Q theory? I assume that it pertains to quantum mechanics?? I thought...

I'm starting this thread since my response to Tom was too long for one post. That's why I said is was misleading and not incorrect. You're giving the impression that there is an overwhelming number of physicists who use the concept you suggest. Let me clarify by example: Suppose it were...

Can anyone help me with something I have been puzzling over on and off for 15 years? I studied Physics at university, but went on to become a computer consultant, and I have forgotten quite a bit. Moreover I have not been able to find anyone willing to take the time to explain it. The...

Plates spinning when they move down and are still when they move up; the plates would have higher mass when moving down then moving up. Should work.

Relativistic Mass as "Gravitational Charge" I've just made a new page for the GR portion of my web site. In it I derived Einstein's field equation but with a different slant. I've decided to go with the "relativistic mass" as source of the gravitational field rather than the "energy as source"...