CHAPTER IV - OSCILLATIONS

Abstract

This chapter discusses some some simple harmonic oscillations. The oscillation of a simple pendulum is an example of small oscillation; this consists of a particle suspended by a string in the earth's gravitational field. The chapter also explains damped oscillations. Undamped oscillations can be caused not only by a periodic external force but also by a periodic variation of the parameters of the oscillating system. This is called parametric resonance. The chapter discusses the mechanism of parametric resonance. In reality, there is always some friction that causes damping of the oscillations. Consequently, for parametric resonance build-up of oscillations to occur, the amplification coefficient κ must exceed a certain minimum value, namely the damping coefficient due to friction. The chapter discusses the production of oscillations in a system by periodic external interaction. There are, however, oscillatory systems in which oscillations are caused not by a periodic force but by a steady source of energy that compensates the energy losses in the system that bring about the damping of the oscillations. One example of such a system is a clock in which a compressed spring or raised weights act as the source of energy.