This monograph was written for the Conference on the New Instructional Materials in Physics, held at the University of Washington in summer, 1965. It is intended for college students who are not preparing to become professional physicists. The monograph contains three chapters. Chapter 1 deals with the law of inertia for objects at rest and in motion, the theory of Galilean relativity and deviations from the law of inertia. The law of momentum conservation and its applications are discussed in chapter 2. In chapter 3, the principle of energy conservation and the concept of kinetic energy are discussed. A number of experiments and problems are included in each chapter. (LC)