In introductory physics courses, it is typically assumed that dry sliding friction is independent of the relative speed of the contact surfaces. However, research in tribology indicates that this assumption is not always correct.1,2 There has been little investigation on this topic in physics education literature,3–5 and the textbooks rarely go beyond the f = μN equation when sliding friction is concerned.6–8 The main objective of this paper is to present a method for determining whether dry sliding friction force depends on the sliding speed of the contact surfaces. To this end, we designed and conducted an experiment in which we varied the relative speed of the contact surfaces from approximately 0.5 m/s to 6 m/s and measured the resulting sliding friction force.
The examined speed range would be appropriate for most introductory physics lab activities or textbook study problems. These include sliding on inclined or horizontal...
