2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/28664One considers the motion of a test particle in an homogeneous fluid in equilibrium at temperature $T$, undergoing dissipative collisions with the fluid particles. It is shown that the corresponding linear Boltzmann equation still posseses a stationary Maxwellian velocity distribution, with an effective temperature smaller than $T$. This effective temperature is explicitly given in terms of the restitution parameter and the masses.5 pages, no figures, submitted to Phys. Rev. LettStatistical Mechanicstext