The moment of inertia of a solid cylinder is $\frac{1}{2}mr^2$, and the moment of inertia of a composite object is the sum of the moments of inertia of the objects it consists of minus the moment of inertia of any air space. That would imply that the moment of inertia of a cylindrical tube is $\f...

In a book Quantum Mechanics with Applications (1970) by D.B. Beard and G.B. Beard, the authors wrote on page 34: "By methods beyond the scope of this text, one could state the uncertainty principle as a fundamental postula and derive quantum mechanics therefrom." Were they trolling or was that ...