Vibration of the oscillator exchanging mass with surroundings

Vibration of two simple open systems (namely the linear mass-sprins oscillator and the mathematical pendulum) are investigated. During the motion, the body absorbs matter through its boundary. In both cases, mechanism of mass absorption is modeled as a perfectly 'inelastic' collision and constant rate of mass change is assumed. The paper is focused on the influence of mass change on the kinematic aspects of oscillations.