“Mechanics is the science of motion; we define as its task: to describe
and in the
simplest possible manner
such motions as occur in nature.” With respect to engineering we should complete this statement by “as occur in nature and in technology.” This more than a hundred-year-old statement was made by
 and has lost neither its meaningfulness nor its assertion. Technical mechanics as a science must also be as simple as possible but conversely descriptively complete. If we consider motion as any kind of translation and rotation, even if only minimal as in the case of deformations, and also include the state of no motion (i.e., the state of rest), then motion describes mechanics as a whole. It comprises two fundamental aspects, that of geometry and kinematics describing positions and orientations, velocities and accelerations, and that of kinetics, describing the cause of motion. Regarding all possible interactions between material bodies or between material bodies and their environment, we consider those possibilities, which produce accelerations (or deformations) of these bodies. We call the driving magnitude of such interactions
. Thus, the kinematics of bodies and their interaction with forces, their statics and kinetics, define mechanics.