A sophomore in physics seeks recommendations for free online books on classical mechanics and vibrations and waves. Several resources are shared, including lecture notes from universities such as the University of Miami and UT Austin, which provide comprehensive materials on mechanics. Specific links to free PDFs are provided, including "Classical Mechanics: A Critical Introduction" and course materials from UT Austin. The discussion also touches on the legality of sharing certain textbooks, with a participant acknowledging the potential copyright issues of a recommended PDF. The conversation humorously explores the idea of reading physics textbooks in various situations, emphasizing the importance of utilizing time effectively for study.