  Mechanics can be founded in a principle stating the uncertainty in the
position of an observable particle delta-q as a function of its motion relative
to the observer, expressed in a trajectory representation . From this
principle, p.delta-q=const., being p the q-conjugated momentum, mechanical laws
are derived and the meaning of the Lagrangian and Hamiltonian functions are
discussed. The connection between the presented principle and Hamilton's Least
Action Principle is examined.
  For a particle hidden from direct observation, the position uncertainty is
determined by the enclosing boundaries, and is, thus, disengaged from its
momentum. Heat, as a non-mechanical magnitude, stem from this fact, and
thermodynamical magnitudes have direct expression in the presented formalism.
  It is finally shown that in terms of Information Theory, mechanical laws have
simple interpretation. Kinetic and potential energies are expressions of the
information on momentum and position respectively, and the law of conservation
of energy expresses the absence of information exchange in mechanical
interactions.
