Work and energy, repose and lethargy
First we show the work and energy in the linear motion of a particle with space-time (see J.M. Knudsen and P.G. Hjorth’s Elements of Newtonian Mechanics, 1995, p.51). Consider a particle of mass m moving along the r axis of r so all quantities are scalars. Newton’s second law is then m d²r/dt² = F, […]