A string of area of cross-section 4mm2 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 ____×10−5
(use Young's modulus 1011N∕m2 and g=10m∕ s2 )