Two identical rollers are mounted with their axes parallel, in a horizontal plane, a distance 2d = 21.6 cm apart. The two rollers are rotating inwardly at the top with the same angular speed (w). A long uniform board is laid across them in a direction perpendicular to their axes. The board of mass m = 3.52 kg is originally placed so that its center of mass lies a distance x(initial) = 10 cm from the point midway between the rollers. The coincident of friction between the board and rollers is k = 0.653. What is the period (s) of the motion?

m -2d-