Abstract:

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