The edge of a nucleus can be roughly modeled as a square potential barrier. an alpha particle in an unstable nucleus can be modeled as a particle with a specific energy, bouncing back and forth between these square potential barrier. consider a nucleus of radius r and an alpha particle with kinetic energy e (i. e., let the potential energy within the nucleus be zero) and mass m. assuming that the alpha particle moves along a diameter of the nucleus and that it moves at low enough speed that relativistic effects are negligible, what is the time tau between successive encounters between each edge of the nucleus and the alpha particle?