In this course we will study how the universe works. Okay, I know
that sounds like a grand plan; but, trust me, it is an accurate description
of physics. Not only will we learn how large systems (the moon orbiting
about the earth, for example) behave, but the same principles also govern
how everyday objects such as baseballs and rockets move. It's this
universality of classical mechanics that is so amazing. In fact, this
idea of having a single concept (or just a few) describe many different
systems is at the core of physics.
Physicists (and other scientists) search for fundamental principles. When a physicist (or physics student!) sees a problem they first ask themselves "what are the fundamental principles at work here?" I'm not going to claim that this is an easy thing to do. Many systems are very complicated and it takes some time determine what is going on. One must stay focused on the task of sorting out the fundamentals from the extraneous information.
Why do we study classical mechanics first? Why not jump into the physics of blackholes or quantum computers? Classical mechanics is valid for an amazing number of systems; admittedly, we do have to modify it to accurately describe extremely large objects (general relativity), very fast moving objects (special relativity) or small objects (quantum mechanics). You can almost play "six degrees of separation" with classical mechanics- every field of physics is, in some way, an offshoot of classical mechanics. In order to understand how your computerís processor functions you need to learn about condensed matter physics (the physics of solids and liquids) which is based upon quantum mechanics and thermodynamics (the physics of heat and energy). And, guess what? Those are directly related to classical mechanics.
Below I've sketched a "concept map" that shows some of the connections between various areas of physics. It is by no means complete; if it were, there would be many more connections. For example, one relatively new field of study is sonoluminescence where one can produce light from sound pulses. Also, chaos theory has been connected to nearly every area of physics (and many non-physics fields such as economics). If one wanted, you could even extend the map to connect with the other science and engineering fields.- e.g. condensed matter physics is intimately related to physical chemistry.