Have a look at the forum rules here...
A bar of steel has following properties:Se=250MPa, Sy=500MPa and Su=800MPa for a reliability factor of 92%. For each of the cases below, when all the correction factors apart from Kc are equal to 1, find the factor of safty guarding against a static failure and either the factor of safty guarding against a fatigue failure or the expected life of the part with a reliability factor of 95%.
(a) A tortional stress between 250MPa and -150MPa(negative)
(b) the previous situation (a) with an added steady tensile stress of 50MPa
Or -- better yet, consult the course notes. I have never seen a homework question set that had not yet been covered in basis in the Notes or Lectures.
Is this really how you think you will behave as a qualified Engineer, should you ever graduate? Will this be your response when asked to design a structure? "OK boss, give me a few days to find out the answer on the Internet..."
Hit the books and don't be so lazy Pipper!