I wrote up some notes on acceleration in spacetime.
Example: Quick question:
If Moe is moving rapidly relative to the lab frame, and is
undergoing a proper acceleration a (as measured in Moe's frame),
what is the 3-acceleration observed in the lab frame?
This is new and may need debugging. Suggestions for how to
improve it are always welcome.
It is intriguing and perhaps pedagogically valuable to compare
my calculation with http://physics.nmt.edu/~raymond/classes/ph13xbook/node59.html
which is AFAICT fundamentally the same calculation ... but it
sure looks different, due to a different representation of the
key quantities.
FWIW I find the sinh/cosh/rapidity representation clearer.
That's how I was taught.
As always, a true master of the subject should be able to see
things either way, using either representation ... but I really
have to struggle to follow the sqrt(1 - v^2/c^2) representation.
It seems to obscure the geometrical significance of the results.