A string of area of cross-section $4 m{m}^2$ and length 0.5m is connected with a rigid body of mass 2kg. The body is rotated in a vertical circular path of radius 0.5m. The body acquires a speed of 5m/s at the bottom of the circular path. Strain produced in the string when the body is at the bottom of the circle is ______$\times {10}^{-5}$$\left(y={10}^{11}N/m^2,g=10m/s^2\right)$