Vibration modes of a rotating circular membrane with extremely small thickness are investigated. In the previous papers. the author has conducted theoretical analysis of the membrane's equilibrium states and small vibration modes under gravity. employing the membrane theory of shell of revolution and von Karman's vibration equation and taking buckling of the thin membrane in... https://www.roneverhart.com/Dudley-ASA-Thunder-ZN-Hycon-12-52-300-Softballs-4A-068Y/