Abar of steel has the minimum properties se = 40 kpsi, sy = 60 kpsi, and sut = 80 kpsi. the bar is subjected to a steady torsional stress of 15 kpsi and an alternating bending stress of 25 kpsi. find the factor of safety guarding against a static failure, and either the factor of safety guarding against a fatigue failure or the expected life of the part. for the fatigue analysis use: a) modified goodman criterion. b) gerber criterion. c) asme-elliptic criterion.

Which of the following correctly describes what happens when an atomic bomb explodes? small pieces of fissionable material are joined and form a body with a mass greater than the critical mass, the relative number of neutrons escaping decreases, and a chain reaction and explosion result. large pieces of fissionable matter are brought together quickly and form a body with a mass smaller than the critical mass, the relative number of escaping neutrons increases, and a chain reaction and explosion result.