$3-35$ For each section illustrated, find the second moment of area, the location of the neutral axis, and the distances from the neutral axis to the top and bottom surfaces. Consider that the section is transmitting a positive bending moment about the z axis, Mz$,$ where Mz $=10$ kip $$ in if the dimensions of the section are given in ips units, or Mz $=1\mathrm{.}13$ kN $$ m if the dimensions are in SI units. Determine the resulting stresses at the top and bottom surfaces and at every abrupt change in the cross section.