Some kind folks at Caltech have made the legendary 1964 Feynman Lectures on Physics (book by Feynman, Leighton, Sands) available online for free. Well, so far, you may only read Volume I but Volumes II and III should be added in a foreseeable future.
The mathematics is typed using the newest MathJax \(\rm\LaTeX\), just like you're used to from this blog.
The URLs are:
I personally recommend Feynman's lectures for their pragmatic, nearly engineering approach and for the extra depth that Feynman actually possessed while he was presenting these seemingly (and sometimes not just seemingly) simple topics in physics.