Ok, unless you give particular interpretations to "total" mass. Better to say "system" mass.Quote from: LightarrowHowever I don't like to call m "rest" mass because nowadays it's simply called "mass" (the so called "relativistic mass" is an obsolete term and concept).How far off the mark would I be if I interpreted this as saying: "rest" mass = total mass;
"relativistic mass" = inertia?Do you like a concept of inertia which is different along different directions? Along the direction of the body's velocity you have a value of inertia, that is: γ3m, where γ is the gamma Lorentz factor:
γ = 1/sqrt[1-(v/c)2];
in the ortogonal direction you have a different value, that is: γm.
Conclusion: better not to talk about relativistic mass at all.
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