'1) Consider a steel rod under pure tension loading: The rod will fail if the applied stress on the rod cross-sectional area exceeds the steel yield stress. The yield stress R of the rod and the loading stress On the rod S are assumed to be uncertain and modeled by uncorrelated normal distributed variables_ The mean values and the standard deviations of the yield strength and the loading are given aS HR 350 MPa, OR 35 MPa and Hs 200 MPa, Os 40 MPa respectively. Calculate the safety index 8 and the probability of failure pc:'