Patrick Pihl
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Stretching a rubber band increase its mass due to e=mcc, but how?
What do you think is the definition of the mass of an object?Patrick Pihl said:Stretching a rubber band increase its mass due to e=mcc, but how?
PeroK said:What do you think is the definition of the mass of an object?
A better example than the rubber band is the hydrogen atom: one proton and one electron. The mass of the atom, however, is less than the mass of the proton plus the mass of the electron. The difference is the binding energy released when the atom is formed. The same energy is required to ionise the atom by separating the two particles.Patrick Pihl said:Number and kind of particles in the object?
This is not correct. The classical definition of the (inertial) mass is related to an objects resistance to acceleration. In relativity, it is related to the energy content of an object in its rest frame. It then turns out that this also is the inertia of the object, which is one of the great insights from special relativity!Patrick Pihl said:Number and kind of particles in the object?
Patrick Pihl said:Stretching a rubber band increase its mass due to e=mcc, but how?
It does not. What is called "relativistic mass" is an antiquated concept. See my PF Insight on relativisic mass (link in my signature). When we talk about mass today we talk about the invariant mass of a system.Patrick Pihl said:when knowing that mass also increase with speed.
It's not just a matter of "today." Even forty years ago when I was a grad student in experimental elementary particle physics, everyone that I worked with used "mass" to mean "invariant mass" a.k.a. "rest mass."Orodruin said:When we talk about mass today we talk about the invariant mass of a system.
Patrick Pihl said:I should have thought about that myself when knowing that mass also increase with speed.
Mister T said:This confusion is best remedied by never introducing relativistic mass.
I do. It turns out relativistic mass is imaginary.DrStupid said:Too late - unless you have a time machine.
And if anyone is curious about how faster than light implies time travel... Google for "tachyonic anti-telephone" and (more seriously) for "closed time-like curve".Ibix said:For anyone not getting the joke: it turns out that traveling faster than light allows time travel (unless you restrict the allowable velocities somewhat). But anything with a real rest mass traveling at v>c would have an imaginary relativistic mass.