Kinematics

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  • a. The science of pure motion, considered without reference to the matter or objects moved, or to the force producing or changing the motion. (Cf. KINETICS 1.)
  • b. The kinematic features or properties of something. Const. as sing. or pl.


Description

Kinematics (from Greek κίνειν, kinein, to move) is a branch of classical mechanics which describes the motion of objects without consideration of the causes leading to the motion. The other branch is dynamics, which studies the relationship between the motion of objects and its causes. Kinematics is not to be confused with kinetics, and to dynamics as used in modern day physics; this term is no longer in active use. (See dynamics for details.)

It is natural to begin this discussion by considering the various possible types of motion in themselves, leaving out of account for a time the causes to which the initiation of motion may be ascribed; this preliminary inquiry constitutes the science of Kinematics. — Whittaker, E. T. (1)

The simplest application of kinematics is for particle motion, translational or rotational. The next level of complexity is introduced by the introduction of rigid bodies, which are collections of particles having time invariant distances amongst themselves. Rigid bodies might undergo translation and rotation or a combination of both.

A more complicated case is the kinematics of a system of rigid bodies, possibly linked together by mechanical joints. The kinematic description of fluid flow is even more complicated, and not generally thought of in the context of kinematics.

Reference

1. Edmund Taylor Whittaker & William McCrea (1988). A Treatise on the Analytical Dynamics of Particles and Rigid Bodies. Cambridge University Press. First Chapter ISBN 0521358833. [1].