  The classical model of an oscillator linearly coupled to a string captures,
for a low price in technique, many general features of more realistic models
for describing a particle interacting with a field or an atom in a
electromagnetic cavity. The scattering matrix and the asymptotic in and out
waves on the string can be computed exactly and the phenomenon of resonant
scattering can be introduced in the simplest way. The dissipation induced by
the coupling of the oscillator to the string can be studied completely. In the
case of a d'Alembert string, the backreaction leads to an
Abraham-Lorentz-Dirac-like equation. In the case of a Klein-Gordon string, one
can see explicitely how radiation governs the (meta)stability of the
(quasi)bounded mode.
