Mechanics is the study of motion.

In this course we study Newtonian mechanics, which is an excellent theory for describing and understanding the motion of normal, every-day objects doing normal, every-day things. It has been an extremely successful theory, and scientists and engineers have used it to understand a big chunk of the world, and to produce an amazing range of technological structures and devices. However, for understanding the motions of very tiny things (insides of molecules, atoms, subatomic particles, etc.) we need a more advanced theory (quantum mechanics), which you'll learn about in advanced studies. For understanding the motions of things that move at a significant fraction of the speed of light, we again need a more advanced theory (special relativity).

Kinematics is the mathematical description of motion. The first three chapters of our textbook (and therefore the first three lectures) are devoted entirely to kinematics.

Causality is a fundamental principle of Newtonian mechanics, and indeed a fundamental principle of science: Things happen for a reason. The reasons for which motion happens involve the concept of a force, which we shall discuss beginning in Chapter 4.

Many complex types of motion are possible, as you will know from your own experience of living in this world. As usual, we'll begin with the simplest type of motion (motion in a straight line), and leave more complex types of motion for later in the course, and for subsequent courses.