Consider the structural system shown in the figure under the action of weight W. All the joints are hinged. The properties of the members in terms of length (L), area (A) and the modulus of elasticity (E) are also given in the figure. Let L, A and E be 1 m, 0.05 m2 and 30 × 106 N/m2, respectively, and W be 100 kN.Which one of the following sets gives the correct values of the force, stress and change in length of the horizontal member QR?

• A. Compressive force = 25 kN; Stress = 250 kN/m2; Shortening = 0.0118 m
• B. Compressive force = 14.14 kN; Stress = 141.4 kN/m2; Extension = 0.0118 m
• C. Compressive force = 100 kN; Stress = 1000 kN/m2; Shortening = 0.0417 m
• D. Compressive force = 100 kN; Stress = 1000 kN/m2; Extension = 0.0417 m