Introduction

The subject of dynamics is concerned with the relationship between the forces acting on a physical object and the motion that is produced by the force system. Our concern in this text shall be situations in which the classical laws of physics (i.e., Newtonian mechanics) are applicable. For our purposes, we may consider this to be the case whenever the object of interest is moving much more slowly than the speed of light. In part, this restriction means that we can use the concept of an absolute (i.e. fixed) frame of reference, which will be discussed shortly.

A study of dynamics consists of two phases: kinematics and kinetics. The objective of a kinematical analysis is to describe the motion of the system. It is important to realize that this type of study does not concern itself with what is causing the motion. A kinematical study might be needed to quantify a nontechnical description of the way a system moves, for example, finding the velocity of points on a mechanical linkage. In addition, some features of a kinematical analysis will always arise in a kinetics study, which analyzes the interplay between forces and motion. A primary objective will be the development of procedures for applying kinematics and kinetics principles in a logical and consistent manner, so that one may successfully analyze systems that have novel features. Particular emphasis will be placed on three-dimensional systems, some of which feature phenomena that you might not have encountered in your studies thus far.