ABSTRACT
Preliminary remarks. Mechanical motion is change in the location of a body with respect to other bodies. This definition implies that mechanical motion is relative. In order to describe motion, one should specify a frame of reference, which includes a body of reference, a coordinate system fixed relative to the body, and a set of clocks synchronized with one another. Mechanics studies motions of model objects, a point particle (or a point mass) and a rigid body. The location of these objects is determined by a finite set of independent parameters; the objects are said to have finitely many degrees of freedom. Kinematics deals with the characterization of motion without finding out its reasons.
