In general, mechanics studies the laws of motion. The basic idea is that physical objects exert forces on one another during their interactions, and it is the forces, or lack thereof, that eventually determine motion. For the most part, classical mechanics was developed by observing solid objects in our environment, including heavenly bodies.
In the following, some of the core concepts, laws and assumptions of classical mechanics are presented. We focus on rigid objects, because it suffices for our purposes.