Rotation in secondary school: teaching the effects of frictional force

Abstract

Frictional force is a source of misconceptions among students, as teachers know from daily experience. This is confirmed by many studies carried out by investigators from all over the world. Surprisingly (or perhaps not), we have found some of these misconceptions among physics school teachers and senior students of physics education courses participating in a workshop in Portugal. In this article we discuss conceptual problems involving frictional force in rotating bodies and suggest teaching strategies based on problem solving, in order to ensure meaningful learning of this difficult topic.

Forces on wheels and fuel consumption in cars

“…These equations are similar to those given in ref. [2], for the case of a bicycle. In the case of an accelerating bicycle the tractive wheel is the rear one.…”

“…On that wheel the static friction force points forwardly (our F in the car) whereas in the front wheel the static force points in the backward direction (our f in the car). The example or the car and the example of the bicycle, studied in [2], are good and equivalent pedagogical examples to discuss the static friction forces on wheels. If we write I = 1 2 m ′ R 2 (assuming a cylindrical wheel), where m ′ is the "effective" wheel mass (actually not the real mass because the wheel is not homogeneous), the previous equations reduce to…”

Concept Acquisition of Rotational Dynamics by Interactive Demonstration and Free-Body Diagram

“…The most important concept is about force and motion (Carvalho & Sousa, 2005). Hence, such concept is crucial to be studied and mastered by students (Robinson, 2014).…”

Video-Based Analysis of the Transition from Slipping to Rolling

“…In addition, students have difficulty understanding that frictional forces can act in the direction of motion-i.e. , they can accelerate objects [3][4][5][6].…”