Energy and the Confused Student II: Systems

Abstract

Energy is a critical concept in physics problem-solving but is often a major source of confusion for students if the presentation is not carefully crafted by the instructor or the textbook. The first article1 in this series discussed student confusion generated by traditional treatments of work. In any discussion of work, it is important to state that work is done on a system by a force. This phrasing has two important components: (1) the identification of the force that is doing the work and (2) the identification of the recipient of the work as a system. Very few textbook or lecture presentations use a system-based approach when performing an energy problem. The first two steps in approaching any energy problem should be: 1) Identify the system; 2) Categorize the system