My search for a book with extremely hard physics problems(conceptual or a problem to solve) had led me to a couple books like "Pathfinder for Olympiad and JEE (Advanced) Physics", "I.E Irodov", "S.S Krotov" and the "200 Puzzling Problems in Physics" series over the past couple months and other books that I had seen on the internet doesn't have more difficult problems.
Are there any books/resources which you have seen which has even harder problems?
I am currently specifically looking for problems related to mechanics (Kinematics, Rotational Dynamics, etc).
A hard problem is a defined such that it uses a unique hard to grasp logic that you would have to think a lot in order to solve and is not a question which requires you to solve a exorbitant amount of equations or calculate very complicated derivatives or integrals.