QUESTION #4 - Trusses 10 kN -2 m- 5 kN 4 m G 45 H 2 m E E K B [20 marks] Figure 3 (Courtesy of Prentice Hall, Adapted) As shown in Figure 3, a truss is designed to support a staircase to move between two horizontal surfaces at two different heights A and B. the truss is subjected to two forces forces as shown, applied at H and J. Note that all the triangles in the portion of the truss ACJI are equilateral triangles, having one angle of angle 45 and two sides of length 2 m. Also the 5-kN force is applied perpendicular to AI. (a) Determine the reactions at the truss' supports. [4 marks] (b) Use method of joints to determine the force in member HI. Indicate if the member is in tension or compression. [10 marks] (c) Use method of sections to determine the forces in members HI, HE and DE. Indicate if the member is in tension or compression. [6 marks]