Does anyone know of any "crash courses" in various physics topics such as classical mechanics, quantum mechanics, theories of relativity, field theories, etc free online? By "crash courses" I mean PDF's for example with good examples, since I learn the quickest with examples. I know it is rather specific but if anyone knows that would be great. I only ask if you are already familiar with some and would like to recommend them to me, I'm not asking anyone to google for me. Thanks.