This paper proposes an experiment seeking to demonstrate that for the static frictional force there is conservation of energy. The experiment consists of a sphere rolling down in a rough inclined plane, for which the slope can be varied. For each given angle the mechanical energy in the beginning and at the end of the movement was determined. The analysis of the results showed that the conservation of the mechanical energy occurs up to a maximum angle, starting from the one which the sphere begins to slide. The determination of this angle by graphic inspection allowed the calculation of the coefficient of static friction between the bodies.
