A shaft with a circumferential groove is subjected to bending, as in Fig. A.12(c). The bending moment is M = 140 N ∙ m, and the dimensions are d ₂ = 20, d ₁ = 15, and p = 2.5 mm. It is made of a titanium alloy with yield strength α ₀ = 930 MPa. In a tension test, as in Fig. 1.3, this material exhibits reasonably ductile behavior, finally breaking at a strain around ε _f = 14%. What is the safety factor against large amounts of deformation occurring in the shaft due to yielding? Does the value seem adequate? (Comment: Note that the stress units MPa = N/mm ² .)