Understanding the effect of rolling friction in the inclined trackexperiment

• Published in: Physics education 2020-09, Vol.55 (5), p.055010
• Main Authors: Maslova, K, V L B de Jesus, Sasaki, D G G
• Format: Article
• Language: English
• Subjects: Acceleration; Coefficient of friction; Friction; Laboratories; Laboratory Equipment; Physics; Rolling resistance; Static friction
• ISSN: 0031-9120; 1361-6552
• DOI: 10.1088/1361-6552/ab9217

In general, undergraduate experimental physics laboratories do not usually haveexperiments designed to address rolling friction and to measure the value of therolling friction coefficient. This work explores an experiment, which has thepotential to arouse students’ curiosity about rolling friction byaddressing a counterintuitive aspect of the behavior of a sphere that rolls up,stops and then rolls down on an inclined track. In fact, due to the differencein the net static friction in the upward and downward movements caused by therolling friction term, the sphere’s acceleration when rolling upward ishigher than when rolling downward. This difference, which had been predictedtheoretically, was easily demonstrated graphically by video analysis, using bothrubber and mouse balls. For two steel balls, this difference was more subtle,but it was still possible to detect it numerically. The experimental setupemployed typical laboratory equipment and the free video analysis softwareTracker to collect position and velocity data. The rollingfriction coefficient was calculated with good precision by means of an angularcoefficient of a fitted first-degree function involving appropriatevariables.