Deriving and applying Newton^s PQRST formula with pre-service phyiscs teachers
Yuvita Oktarisa1 (a*), Ricardo Karam (b)

(a) Department of Physics Education, Sultan Ageng Tirtayasa University, Indonesia
(b) Department of Science Education, Universitas of Copenhagen, Denmark

Abstract

One of Newton^s greatest scientific achievements was to show that Kepler^s first law follows from the assumption of an inverse-square central force. Despite its importance, this connection is rarely taught in physics courses at introductory level due to the mathematical complexities involved in the proof. A possible didactic solution to this problem is to focus on a conceptual understanding of Proposition VI of Newton^s Principia. In this paper, we report a study conducted with the goal of teaching pre-service physics teachers key aspects of Proporsition VI, as well as its application to determine the force law, given the orbit shape and the sun^s position. Our findings consist of students^ interpretations and difficulties when trying to understand Newton^s original reasoning.

Keywords: PQRST formula, Principia, Students^ difficulties

Topic: Physics Education