The fracture toughness of a given steel is 60 MPa-m^^^ and its yield strength is given by O-Q (MPa) = XXXXXXXXXX4T, where T is the temperature in degrees Kelvin. Surface cracks measuring 0.001 m are...

The fracture toughness of a given steel is 60 MPa-m^^^ and its yield strength is given by O-Q (MPa) = 1400 - 4T, where T is the temperature in degrees Kelvin. Surface cracks measuring 0.001 m are detected. Under these conditions determine the temperature at which there may be a ductile-brittle transition in this steel.