A small ball of mass m attached at the midpoint of a tightiy stretched elastic cord of len...

A small ball of mass m attached at the midpoint of a tightiy stretched elastic cord of length / can slide on a horizontal plane. The ball is give a small displacement in a direction perpendicular to the cord and released.Assuning the tension Tin the cord to remin constant (a) writehe differential equation of motion of the ball (b) determine the period of vibration.