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In this note, quasistatic solutions of a two-mass-two-spring Tomlinson model for atomic force microscopy are derived, and are compared with the corresponding results of the single-spring Tomlinson model. It is clarified that the solutions of the two models are equivalent provided that the effective spring constant is correctly defined. It is also shown that modeling the onset of stick-slip motion in terms of the criteria defined by explicit tip and cantilever stiffness is the most convenient to investigate the effects of the tip-flexibility on the stick-slip motion.

A method is introduced to measure friction on small, free standing objects, specifically microfabricated silicon plates, based on atomic force microscopy (AFM). An AFM tip is brought into contact with the plate resting on a substrate. The substrate is displaced laterally and, provided the AFM tip does not slide over the plate, the twisting of the AFM cantilever is used to measure the friction of the underlying plate-substrate interface. The method can measure nano-Newton to micro-Newton forces (both friction and applied load) and provides a means to measure friction of macroscopic structures at low load.