ABSTRACT
Finally, the most important reason to start with ideas of motion is that it is one of the main windows that allows us to understand the nature of forces. We can view the universe as being made up entirely of just four constructs: matter, forces, space, and time. Without matter, of course, there would be nothing in the universe. But without forces, the matter would not be able to interact, and thus would not be able to “clump” up to form atoms or molecules or cells or us. Before we can understand the nature of forces and how we can measure them, we have to rst understand motion and how forces affect motion. Objects in motion move through space and time. We assume these to be absolute in the sense that the distance between two points in space will be the same for all observers, and the time interval for a given event will be the same for all observers. While this seems to be an obvious assumption, we will learn in the chapter on relativity that is it an incorrect one. For now, we can safely avoid these complications in our discussion of motion.
