a) 
gives the intensity of stress uniformly distributed over the cross section in an axially loaded, prismatic bar of arbitrary cross-sectional shape.
i) Axial force P acts through the centroid of the cross-sectional area
ii) Uniform stress condition exists throughout the length of the bar except near the ends
c) Stresses act in a direction perpendicular to the cut surface, they are called normal stresses.
d) Tensile stresses as positive and compressive stresses as negative.
