Talk:Kinetic Energy of Classical Particle

Result or definition
It is not so easy to define the "derivation of kinetic energy". The current broad definition of kinetic energy is actually quite good, since it only relates to motion. However, why should we choose quadratic dependence? One can in principle have any power of velocity multiplied by an arbitrary coefficient called "inertial mass" and call the whole term the kinetic energy. Actually, in theoretical physics there are examples of phantom fields with negative kinetic energy and arbitrary powers of velocities (so to speak). I believe it is better to state a certain equivalence between Newton's laws and Lagrangian (something like equivalence of definitions). As for kinetic energy, the only way to derive in my opinion is through the "body's ability to do work". But it is a bit vague in mathematical sense. I would suggest that first we define a certain function called classical kinetic energy and then show that in certain processes some other functions are generated like a function of work, whose value in absolute magnitude approaches or becomes equal to that of kinetic energy. My logic in Lagrangian mechanics is that kinetic energy is a certain auxiliary function which is quite useful in classical cases. --Julius (talk) 16:52, 9 September 2019 (EDT)


 * We already have a definition of kinetic energy. My thought was that the classical case was derivable from the definition of energy as the integral of velocity with respect to time (or whatever it is, based on whatever it was that I've mostly forgotten from many years ago), in that the "classical" case is the simple one where mass is constant with veolocity. Can't remember the detail now, but I do remember that K.E. is a derived quantity rather than an absolute definition. --prime mover (talk) 17:12, 9 September 2019 (EDT)