A copper bar AB of length 25 in. and diameter 2 in. is placed in position at room temperature with a gap of 0.008 in. between end A and a rigid restraint (see figure). The bar is supported at end B by an elastic spring with spring constant k = 1.2 × 106 lb/in.
(a) Calculate the axial compressive stress c in the bar if the temperature rises 50°F. (For copper, use α = 9.6 × 106 / °F and E = 16 × 106 psi.)
(b) What is the force in the spring? (Neglect gravity effects.)
(c) Repeat (a) if k †’ ˆž

0.008 in. 25 in.