Introduction to Electrodynamics · Problem 12.40

Electrodynamics and Relativity — David J. Griffiths

Physics · minkowski-force

Problem

Show that

K_\mu K^\mu = \frac{1-(u^2/c^2)\cos^2\theta}{1-u^2/c^2}\,F^2,

where

\theta

is the angle between

\mathbf{u}

and

\mathbf{F}