Frame-invariant proper-force

Here we try to find “the best joints for carving up” the phenomenon of accelerated-motion so as to obtain (i)

the least need for extended-networks of synchronized-clocks as well as (ii) the greatest frame-independence.

The acceleration four-vector’s invariant magnitude, and a number of other quantities from the traveler’s

point of view, show promise for broadening student understanding (and perhaps even practical application)

of accelerated motion perspectives at both low and high speeds.