The material selected for the shaft design has an ultimate tensile strength, Sut, of 123 kpsi and a yield strength, Sy, of 94 kpsi. Determine the location of the critical section on the shaft. (You must provide an answer before moving to the next part.)

Aturning operation is performed with following conditions: rake angle of 12°, a feed of 0.35 mm/rev, and a depth of cut of 1.1 mm. the work piece is aluminum alloy 6061 with t6 heat treatment (a16061-t6). the resultant chip thickness was measured to be 1.0 mm. estimate the cutting force, fc. use shear stress of 207 mpa and coefficient of friction on the tool face of 0.6.