Compressive force F = 40 kN = 40000 N,

and cross-sectional area A = π/4 (D^{2} − d^{2})

where D = outside diameter = 25 mm and

d = inside diameter = 15 mm. Hence

(a) Compressive stress

(b) Contraction of pipe when loaded,

x = 0.5 mm = 0.0005 m, and original length

L = 0.40 m. Hence, compressive strain,

ε = x/L = 0.0005/0.4

= 0.00125 (or 0.125%)