Maximizing tangential frictional forces effects in bidimensional collisions: a study of the tangent restitution coefficient through a video analysis approach

Abstract

In this work we used the video analysis technique to investigate the contribution of the friction forces to the dynamic of a series of oblique collisions of a basketball against the floor's surface. This contribution was evaluated through the tangent restitution coefficients associated to these collisions, which, in general, presented values distinct from the unit, proving, thus, its importance. Additionally, the appreciably values bigger than unity obtained for this quantity quantitatively confirms the physical scenario suggested in a previous work by some of the authors [1] which is governed by the torques transmitted to the ball during the successive collisions and characterized by variations on the magnitudes and even on the directions of the friction forces. To support this dynamic we considered a ball of relatively sizeable radius and mass, and launched with a certain spin velocity. Also, in order to increase the friction coefficient, the floor's surface was covered with a rough and rubberized material.