Exploring Magnetic Interactions between Magnets and a Magnetizable Alloy

Abstract

Traditional problems in mechanics usually involve forces that regenerate motions described by analytical solutions, easily obtained from differential equations. However, when magnetic forces are involved, problems can be very complex to describe analytically. Students of introductory Physics courses can benefit from solving questions of unusual complexity, as this broadens their view in more general contexts in Physics. In this paper, we describe the problematic situation of magnets that attract a coin of a magnetizable alloy. The problem is solved analytically, assuming that the force exerted on the coin varies exponentially with the distance between them. The experiment was filmed with a camera at a high rate frame and the experimental values compared with those predicted by the theoretical model. The results confirm that the theoretical model is adequate to describe the kind of interaction involved, showing that these are very different from those usually found in problems with gravitational, electrical or elastic interactions. This work opens up future perspectives for investigations with attractive and repulsive forces between magnets.