Hi, I'm a physicist and former IPhO contestant from Hungary. Unfortunately most of the books I could suggest are Hungarian, but there are some resources in Engl

Hi, I'm a physicist and former IPhO contestant from Hungary. Unfortunately most of the books I could suggest are Hungarian, but there are some resources in English for hard physics problems. KoMaL [1] is a high school competition, students have one month to solve five physics problems (they can solve more, but only the five best is counted each month). Unfortunately older archives are only in Hungarian, but this is an endless resource, you can come back for new problems each month. Ortvay [2] is a yearly take-home, one week long problem solving competition for University students. These problems are _very_ hard, so don't be discouraged by not being able to solve them right away. [3] and [4] are some of my favorite books with Physics problems from Hungarian authors. The problems have varying difficulty, but they are clearly marked in this regard. There are separate hints and full solutions. [1] https://www.komal.hu/verseny/feladatok.e.shtml https://www.komal.hu/verseny/feladatok.e.shtml [2] https://ortvay.elte.hu/main.html https://ortvay.elte.hu/main.html [3] https://www.cambridge.org/gb/academic/subjects/physics/general-and-classical-physics/200-puzzling-physics-problems-hints-and-solutions?format=AR&isbn=9780521774802 https://www.cambridge.org/gb/academic/subjects/physics/gener... [4] https://www.cambridge.org/gb/academic/subjects/physics/general-and-classical-physics/200-more-puzzling-physics-problems-hints-and-solutions?format=HB&isbn=9781107103856 https://www.cambridge.org/gb/academic/subjects/physics/gener...