ABSTRACT
Vibration is a representation of the motion of a body, is essentially oscillatory about a mean position, and can be periodic or aperiodic. This motion of the body can be described in any direction. However, the degree of freedom is the number of independent coordinates that can be used to describe the motions of a rigid body. For example, a rigid body in space has 6 degrees of freedom, which consist of three translatory motions and three rotational motions about these axes. Usually, for a large machinery supported at the four corners on a shop floor, the vibration motion in three directions is measured and analyzed. However, before discussing in details of the motion of bodies in more than one direction, the motion of a rigid mass in one direction is considered in order to get familiar with the associated terminology.
