Physically Incorrect

Just to let you know of two new updates. A ‘rants’ category has been added and will slowly fill up. I’ve also begun noting the level of difficulty of puzzles on the posts’ top-right corners: layperson, highschool,  undergradute and graduate. This merely signifies the amount of prerequisites needed to solve the given problem, NOT how ‘hard’ it is, as ‘hardness’  is somewhat subjective.  For example, a problem involving resistors in parallel will be labelled ‘highschool’. A problem requiring a good grasp of calculus would be classified as ‘undergraduate’. A puzzle having to do with the Hamilton-Jacobi equation or with Lie derivatives would be marked as ‘graduate’.