On the friction of solid bodies
In this paper, Euler inquires into the nature of the force of friction. He proposes a model for understanding friction in terms of gravity, and deduces from this model that kinetic friction should be less than static friction. Euler then proposes an experiment for determining the quantity of kinetic friction using an object descending an inclined plane, and provides the formulas necessary to solve for friction given the specifications of the object's descent of the plane. He also illustrates that, as in implication of kinetic friction being less than static friction, it is impossible to make an object descend a plane infinitely slowly.
Original Source Citation
Mémoires de l'académie des sciences de Berlin, Volume 4, pp. 122-132.
Opera Omnia Citation
Series 2, Volume 8, pp.54-63.