고체역학 (Gere) — Axially Loaded Members: Problem 2.2-3

2.2-3 The L-shaped arm \( ABCD \) shown in the figure lies in a vertical plane and pivots about a horizontal pin at \( A \). The arm has a constant cross-sectional area and total weight \( W \). A vertical spring of stiffness \( k \) supports the arm at point \( B \). (a) Obtain a formula for the elongation of the spring due to the weight of the arm. (b) Repeat part (a) if the pin support at \( A \) is moved to \( D \).