http://www.differencebetween.com/difference-between-inertia-and-vs-mass/
"For classical mechanics, mass is a property of the object itself but inertia is a property of the motion as well as the mass."
I don't believe this. It seems to me that mass is an accident using the word in the substance and accident philosophy term.
When an object moves at close to c the mass of the object increases but the amount of matter doesn't increase. There is still the same number of protons and electrons as when the velocity is much lower.
I believe that mass is a measure of the internal motion of the substance, the matter.
As we all know nowadays but wasn't know in the time of Newton, there in an awful lot of internal motion in materials. Specifically, closed path motion, or to simplify things, circular motion, rotational motion.
to be continued
