Some more Physics/Mathematics puzzles with an unusual structure, tailored for the Google-in-hand generation. In most cases, you don’t have to derive a numerical value for the solution, to remember the value of the physical constants required, or even to remember…

4 Pulleys and Plank A horizontal square plank is held up by one rope at each corner. Each rope passes over a simple pulley and ends in a 10 kg weight that itself rests on the plank. All ropes are…