A 6.8-kg bowling ball is attached to the end of a nylon cord with a cross sectional area of 3.4 × 10⁻⁵ m². The other end of the cord is fixed to the ceiling. When the bowling ball is pulled to one side and released from rest, it swings downward in a circular arc. At the instant it reaches its lowest point, the bowling ball is 1.4 m lower than the point from which it was released, and the cord is stretched 2.7 × 10⁻³ m from its unstrained length. What is the unstrained length of the cord? When calculating any quantity other than the strain, ignore the increase in the length of the cord.)