Extracted text: 2. Determine the vertical deflection at joint B of the truss shown in Fig. below due to a temperature increase of 40° C in members AB and BC, and a temperature drop of 20° C in members AD, DE, EF, and CF. If member BE is 18 mm too long and member BC is 15mm too short. Use the method of virtual work. E 3.5 m D B -6 m- a = 1.2 (10-5)°C