A negative answer to Ulam's Problem 19 from the Scottish Book

Autor: Ryabogin, Dmitry
Rok vydání: 2021
Předmět:
Druh dokumentu: Working Paper
Popis: We give a negative answer to Ulam's Problem 19 from the Scottish Book asking {\it is a solid of uniform density which will float in water in every position a sphere?} Assuming that the density of water is $1$, we show that there exists a strictly convex body of revolution $K\subset {\mathbb R^3}$ of uniform density $\frac{1}{2}$, which is not a Euclidean ball, yet floats in equilibrium in every orientation. We prove an analogous result in all dimensions $d\ge 3$.
Comment: 7 figures. arXiv admin note: text overlap with arXiv:1201.0393
Databáze: arXiv