Fig. 1
From: Anisotropic friction: assessment of force components and resulting trajectories
Top view of the experimental device – The slider (M) is lying on top of a horizontal circular table. The slider is attached to a fixed point P (MP ≡a) while the table is rotated (angular position Ω in the xy frame of the laboratory) thanks to a DC motor. As a consequence of the anisotropy of the substrate, the tangent to the trajectory t makes the angle θ with the direction MP of the applied force. We denote α the angle that t makes with an axis attached to the table. We show here a photograph of the table surface, the black dots corresponding to successive positions of the slider marked with a pen