A word of caution: The Feynman Lectures are copyrighted by Caltech. While you can find PDFs floating around the internet, they are frequently of poor quality (missing equations, scanned upside down) and borderline piracy. Legitimate options exist:
An introduction to general relativity, explaining how gravity is not a "force" in the traditional sense but a curvature of space-time itself. Why "Not-So-Easy"? richard feynman six not so easy pieces pdf
If you read Six Easy Pieces , you learned facts . If you read Six Not So Easy Pieces , you learn intuition . Here are three revolutionary ideas Feynman explains better than anyone else. A word of caution: The Feynman Lectures are
This is where Feynman truly shines. He introduces the profound concept that physical laws do Why "Not-So-Easy"
The title is a playful nod to the increased complexity of the subject matter. Unlike the first collection, which was designed for a general audience with minimal technical background, Six Not-So-Easy Pieces requires a basic grasp of algebra and pre-calculus to fully appreciate the derivations. Six Not So Easy Pieces: Einstein's Relativity, Symmetry…
Because your keyword is "PDF," visual learners need to know:
You need to be comfortable with conservation of energy and basic Newtonian laws before relativity breaks them.