  Criteria for the incipient motion of a rigid body initially resting on a
rigid surface are formulated from first principles in this work. A modified
Coulomb friction model and an associated distribution of reaction forces are
proposed. There exists a surprisingly large category of general motions,
however, which subscribe to a more conventional analysis; an analysis made
possible by identifying so-called ``significant reaction surfaces''. In this
way a model which caters for the majority of combined translations and
rotations is devised. Some introductry results demonstrate the accuracy with
which fluids can be numerically modelled for the purposes of entrainment. This
work is an extension of previous work by the same author.
