A 15.1 mass fastened to the end of a steel wire with an unstretched length of 0.650 is whirled in a vertical circle with angular velocity 2.00 at the bottom of the circle. The cross-sectional area of the wire is 1.20×10?2 . Calculate the elongation of the wire when the mass is at the lowest point of the path in mm.(Young's modulus of steel is .)