A bar AB supports a load P acting at the centroid of the end cross section (see figure) in the middle region of the bar the cross-sectional area is reduced by removing one-half of the bar.
(a) If the end crosses sections of the bar are square with sides of length b, what are the maximum tensile and compressive stresses σt and σc, respectively, at cross section mn within the reduced region?
(b) If the end cross sections are circular with diameter b, what are the maximum stresses σt and σc?

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