DEVELOPMENT OF ENERGY CONCEPTS AND WORK-KINETIC ENERGY THEOREM

In introductory physics courses energy concepts are introduced with work-kinetic energy theorem derived from Newton’s second law considering the motion of center of mass of an object or just invoking the particle model assuming no structure. If not properly addressed, this introduction could leave students with incomplete understanding of work, energy transfer, and energy transformations in macroscopic objects. Students often misinterpret correct dynamical relationships derived from Newton’s second law as an application of work-kinetic energy theorem even when forces such as normal force and frictional forces are considered. Students’ confusions can be seen when they question about how energy of a person is used in calculations when solving a problem related to a vertical leap by a person or how a car gets its translational kinetic energy without any work done by static frictional force etc. Work-kinetic energy theorem is limited in application and it has been suggested that the solution to these problems is to introduce thermodynamic work, first law of thermodynamics with the concept of internal energy as early as possible [1,2,3]. A discussion about proper introduction of work and first law of thermodynamics within energy chapter is presented. 1. Arnold B Arons, American Journal of Physics, 67,1603 (1999), 2. Bruce Ame Sherwood, American Journal of Physics, 51, 597, (1983), 2. John W Jewett, The Physics Teacher, 46,38 (2008