I am a computer science major interested in learning how to create games. I know c++ very well and I am familiar with opengl. I want to know if opengl is just for graphics or can it be used for things like networking, collision detection, and sound for designing a game?
However, things like collision can be implemented for use with OpenGL rendered objects using third party libraries or, of course, you can write you're own, which isn't recommended seems it would take too long; there are already many resources available; one that comes recommended is Havok or there is Bullet Physics for real-time simulation, (you might have more luck asking questions about collision using bullet here).
There are also cross-platform Audio APIs like PortAudio for example.
Ideally, you would just use a third party games/physics engine and include it's libraries much like you would include OpenGL libraries.