OF THE 



UNIVE 



THEORETICAL MECHANICS 



INTRODUCTION. 



1. The science of theoretical mechanics has for its object 

 the mathematical study of motion. 



2. The idea of motion is intimately related to the funda- 

 mental ideas of space, time, and mass. It will be convenient 

 to introduce these consecutively. Thus we shall begin with a 

 purely geometrical study of motion, without regard to the time 

 consumed in the motion and to the mass of the thing moved, 

 the moving object being considered as a mere geometrical 

 configuration. This introductory branch of mechanics may be 

 called the geometry of motion. 



3. The introduction of the idea of time will then lead us to 

 study the velocity and acceleration of geometrical configura- 

 tions. This constitutes the subject-matter of Kinematics proper. 

 The name Kinematics is, however, used by many authors in a 

 less restricted sense, so as to include the geometry of motion. 



4. Finally, endowing our geometrical points, lines, and other 

 configurations with mass, we are led to the ideas of momentum, 

 force, energy, etc. This part of our subject, the most compre- 

 hensive of all, has been called Dynamics, owing to the importance 

 of the idea of force in its investigation. For the sake of con- 

 venience it is usually divided into two branches, Statics and 



PART I I I 



