Eur. Phys. J. E (2016) 39: 74
https://doi.org/10.1140/epje/i2016-16074-9

Regular Article

Coefficient of restitution mediated by a diamagnetic interaction

¹ Instituto Superior de Tecnologías y Ciencias Aplicadas (InSTEC), Salvador Allende esq. Luaces s/n, Plaza de la Revolución CP 10400, POB 6163, La Habana, Cuba
² CINVESTAV-Monterrey, PIIT, Nuevo, 66600, León, Mexico

^* e-mail: jcrs.mty@gmail.com

Received: 5 February 2016
Accepted: 15 July 2016
Published online: 27 July 2016

Abstract

We study how a magnetic bead bounces onto a horizontal diamagnetic conducting plane. The bead, falling down by gravity from a certain height, produces an Eddy current that creates a repelling force. For low velocities the bead is trapped by the surface, for intermediate ones it escapes. In such a case the induced current changes its sign, and so does the force. The balance between diamagnetic and viscoelastic interactions determines the bouncing dynamics. We find experimentally the restitution coefficient as a function of the impact speed of the bead and develop, taking into account simple energetic considerations, a model able to reproduce our findings.