고체역학 (Beer) — Shearing Stresses in Beams: Problem 6.53

6.53 An extruded beam has a uniform wall thickness $t$. Denoting by $V$ the vertical shear and by $A$ the cross-sectional area of the beam, express the maximum shearing stress as $\tau_{max} = k(V/A)$ and determine the constant $k$ for each of the two orientations shown. (a) Square orientation with horizontal and vertical sides of length $a$. (b) Square orientation rotated by $45^\circ$.