Yank and Hooke's constant group theoretically
  We study the second central extension of the (1+1) Aristotle Lie.We find that the first central extension admit four orbits on the dual of second central extension of the (1+1) Aristotle Lie group.The generic orbit is characterised by a Hooke's constant k and a yank y.If the physics of the orbit is studied with respect the evolution in time,it represents an elementary system with internal energy U in a posotion-momentum under the conjugation of a Hooke's force and a damping one proportional to the velocity as in particle mechanics.If the physics of the orbit is studied with respect the evolution in space, it represents an elementary system with an internal momentum P under the conjugation of a kind of Hooke's force and a damping one proportional to a slowness, slowness usually used in time travel waves. 
Joachim Nzotungicimpaye