In similar fashion we could ask the question what are the normal (sn) and shear (t) stresses acting on the area defined by the line segment AC? Another way of asking the same question would be to ask what are the normal and shearing tractions acting on the line segment AC? A traction then, is a component of a force vector acting on a specified surface. Close scrutiny of Figures 2 and 3 reveal that:
and that:
