고체역학 (Beer) — Stress and Strain—Axial Loading: Problem 2.124

2.124 The uniform wire ABC, of unstretched length 2l, is attached to the supports shown and a vertical load P is applied at the midpoint B. Denoting by A the cross-sectional area of the wire and by E the modulus of elasticity, show that, for \(\delta \ll l\), the deflection at the midpoint B is \[\delta = l\sqrt[3]{\frac{P}{AE}}\]