고체역학 (Beer) — Analysis and Design of Beams for Bending: Problem 5.30

5.30 Solve Prob. 5.29, assuming that \( P = 480 \text{ N} \) and \( Q = 320 \text{ N} \). 5.29 (Referenced by 5.30): Knowing that \( P = Q = 480 \text{ N} \), determine (a) the distance \( a \) for which the absolute value of the bending moment in the beam is as small as possible, (b) the corresponding maximum normal stress due to bending. (See hint of Prob. 5.27.) Hint of Prob. 5.27: Draw the bending-moment diagram and equate the absolute values of the largest positive and negative bending moments obtained. Geometry/Loading from Fig. P5.29: Pin support at \( A \). Load \( P \) at point \( C \), distance \( AC = 500 \text{ mm} \). Load \( Q \) at point \( D \), distance \( CD = 500 \text{ mm} \). Roller support at a distance \( a \) from \( A \). Beam cross-section: width \( b = 12 \text{ mm} \), height \( h = 18 \text{ mm} \).