Out with the old rule and in with the new

摘要

During my years of teaching introductory col-lege physics, I have consistently observed that asubstantial fraction of my students have difficultyapplying the right-hand rule that textbooks usu-ally present for determining the direction of vec-tor cross products. Last year for the first time Icompletely abandoned the commonly stated right-hand rule for a simpler equivalent rule. I state herethe only rule I now use in class for finding thedirection of cross products and discuss why I findit advantageous to eliminate the familiar rulefrom my instruction of cross products.