Resources
“An investment in knowledge pays the best interest.”
Useful Resources for Starting Out
The knowledge and resources required for physics olympiads is very similar to the introductory physics syllabus at university. This is great, because it means you can take advantage of some of the truly excellent resources that are available for undergraduate physics.
Online courses
Yale’s Fundamentals of Physics courses, taught by Professor Ramamurti Shankar are wonderful. Prof. Shankar is also very funny! You can find YouTube playlists of the lectures on the YaleCourses channel: here is a playlist for the first of the two courses, which introduces the basic principles of mechanics, waves, and thermodynamics. The video lectures for MIT’s 8.01 and 8.02 courses are another great resource, filled with interesting experiments.
Textbooks
A standard textbook is Fundamentals of Physics by Halliday, Resnick, and Walker. A more advanced version is written by Halliday, Resnick, and Krane. These textbooks are great introductions, and they are both really common: you will probably encounter them as you study physics in one way or another. To get a deep understanding of Newtonian mechanics (which is essential), Introduction to Classical Mechanics by Morin is really useful.
Problem Sources
A standard textbook is Fundamentals of Physics by Halliday, Resnick, and Walker. A more advanced version is written by Halliday, Resnick, and Krane. These textbooks are great introductions, and they are both really common: you will probably encounter them as you study physics in one way or another. To get a deep understanding of Newtonian mechanics (which is essential), Introduction to Classical Mechanics by Morin is really useful.
Other Resources
At https://www.ioc.ee/~kalda/ipho/ you can find several handouts, a formula sheet for IPhO, and many other resources made by Jaan Kalda. At https://physoly.tech/ you can find solution manuals for Kalda’s handouts and many other resources, as well as a link to a Discord server with thousands of other high school students preparing for physics competitions.
For the resources listed here, it’s really important to have a good understanding of algebra, pre-calculus (such as trigonometry), and calculus. If you’re looking for more advice/resources for starting out (such as physics textbooks that do not require calculus), take a look at https://knzhou.github.io/writing/Advice.pdf, which helped me a lot in writing this.
If you want to gain a deeper understanding of certain topics or go beyond Olympiads, there are a bunch of great resources listed at https://knzhou.github.io/writing/AdviceAfter.pdf.