ABSTRACT
Alternating processes or movements which, to some extent, repeat themselves in time are usually called oscillations or vibrations. Oscillations in physical systems are followed by alternate transformations of energy from one kind to another and back. Natural oscillations in the absence of friction, that is, in idealized conservative systems, are non-damped and exactly periodic. Natural oscillations are accompanied by energy transformations from one kind of energy to another and backwards. At dry friction, damping of oscillations goes on in another way. Coupled pendulums give an example of a system with two degrees of freedom, in which oscillations corresponding to different modes occur along one direction. Wave processes are extremely diverse and occur almost in every field of physical phenomena. The principal laws of wave phenomena are valid for waves of any physical nature, including electromagnetic waves, i.e., for the process of propagation of oscillating electric and magnetic fields coupled with each other.
