University Physics
This book strikes an effective balance between rigor and breadth. It introduces key concepts slowly enough to help many beginners become comfortable with Physics concepts without being overwhelmed. It also allows for a dependable reference for more advanced students, who can cover the material more quickly but will not be bored by the presentation. I worked some of the advanced challenge problems given throughout and they seemed to be sufficiently rigorous for an advanced student to challenge herself or himself.
The content seems thorough and accurate throughout. The one not-quite error I found was in the chapter on sound which presented resonance pipe antinodes occurring at open ends and nodes at closed ends. This is true but only for displacement, not pressure, which is at least misleading since all of sound covered up to that point dealt with pressure, and the diagrams didn't clearly state what was being measured.
This is the best free general physics textbook I have found so far, and it provides examples and application points which point to relevant technology and cultural phenomena, but usually in a general enough way that it does not require a separate update every 5 years. One exception is the photo of an early iPhone as an example of GPS - it already looks a bit dated given the pace of cell phone updates, and I expect it will seem moreso to students as time goes on, given the familiarity of this generation with the latest in smartphone technology.
I liked the text pretty well. A couple of times it seemed they were glossing over something or leaving something as a challenge problem without fully grounding it in theory, but this was the exception rather than the rule.
The book is pretty consistent, although the order of presentation of subject necessitates some fluctuation on that count. Later chapters on waves and sound go back and forth between being a bit over-didactic, introducing lots of concepts, and then being extremely mathematical, referencing concepts such as kinetic and potential energy of the wave, introducing lots of equations. I expected the book overall to be more consistently math-y throughout, but the use of text blocks to introduce other applications was not uncalled for, and I think many students would respond positively to it.
I am considering using part of this textbook for a graduate course on acoustics that I teach. It will need to be supplemented with other sound-centric materials since even this book's chapters on sound focus more on physical acoustics than perception of sound or musical sound. Still, there were some diagrams and sections that were better than some texts I have used in the past, and since it's free I don't have to worry about students paying $200 for a text they only read part of.
I would have restructured the order of some of the concepts, probably waiting on waves until after a more thorough introduction of Newtonian mechanics and E/M. But these are always contentious issues in physics education.
Once I increased the text size, the online version was fairly easy to read. Sometimes I did not care much for the format, layout, text-to-space ratios, etc, but those may be different in the pdf version. Some of the photo figures likewise do not seem to be neatly formatted.
I didn't notice any grammatical errors.
In the sense that physics is trying to study the universal, so too does this book. There are some unavoidable cultural references in the application points, but those seem considered and not focused on any one place or people group.
In general, this is a good book for intro physics classes. I will probably not make it my only textbook for my acoustics course, but I may use it so supplement some wave concepts here and there.