A large plate is fabricated from a steel alloy that

A large plate is fabricated from a steel alloy that has a plane strain fracture toughness of 55MPavm (50ksivin) If, during service use, the plate is exposed to a tensile stress of 200MPa (29,000psi), determine the minimum length of a surface crack that will lead to fracture. Assume a value of 1.0 for Y.