Coupling between static friction force and torque for a tripod

Abstract

If a body is resting on a flat surface, the maximal static friction force before motionsets in is reduced if an external torque is also applied. The coupling between thestatic friction force and static friction torque is nontrivial as our studies for atripod lying on a horizontal flat surface show. In this paper we report on a seriesof experiments that we performed on a tripod and compare our findings withanalytical and numerical solutions. It turns out that the coupling between force andtorque reveals information about the microscopic properties at the onset of sliding.