Mechanical energy analysis of a boomerang mechanism

Abstract

In this paper, we present a comparison of classical theory with video analysis techniques to teach kinetic and potential energy of a device with a boomerang effect as an observable and measurable concept. The device can store energy through an elastic band when it rolls down an inclined plane, and can release the energy when it rolls on a horizontal surface; hence, it receives the name boomerang. In theoretical terms, the details of energy charge and discharge processes are analyzed with Newton's laws and Lagrangian method. The experimental results were recorded with cell phone cameras and processed with an open-source video analysis software, called "Tracker". The comparison shows relevant concepts about kinetic and potential energy, which can help the student to overcome some of the typical student misconceptions.