The Variation of University Physics Students' Experience of Plus and Minus Signs in 1D Vector-kinematics Revisited

This article revisits and expands upon a previous phenomenographic study characterising the qualitatively different ways in which South African undergraduate physics students may experience the use of +/- signs in one-dimensional kinematics (1DK). We find the original categorisation as applicable for interpreting Swedish university-level students' responses to 1DK questions. However, by way of a typology of potential learning outcomes associated with +/- signs in 1DK, our review of the topic reveals that the original study's treatment misses the implications of +/- signs related to time rate of change and graphical shape. We also add to the description of students' experience of +/- signs in 1DK by incorporating ideas from the Variation Theory of Learning and by focusing on some of the aspects of +/- signs in 1DK that were underemphasized in the original study. Our analysis thus provides a template for physics educators to support students' conceptual understanding of sign conventions in vector kinematics