A 250mm plate of a 4340 steel is tested for quality control purposes. It fails at a stress of 550MPA and the modulus is measured as 21OGPA. Examination of the fracture surface shows that failure of...

I need answer of question 4 only

Extracted text: A 250mm plate of a 4340 steel is tested for quality control purposes. It fails at a stress of 550MPA and the modulus is measured as 21OGPA. Examination of the fracture surface shows that failure of the steel was due to the presence of an internal flaw which was measured to be 1mm in length. What is the toughness of the plate? Express your answer in MPa/m. Useful formulae: K = oTa 30.027 Question 4 If the 250mm plate of 4340 from Question 3 is to be used to make a shaft which experiences a maximum load of 200MPa and an internal falw size of 4mm, is the plate safe to use to manufacture the shaft? Select either "True" or "False" as your answer. Useful formulae:K = o/na