An arched roof truss is installed as shown in the truss structure $($a$)$ Calculate the support forces by drawing the free body diagram. $($b$)$ Calculate the forces in the elements FH$,$ GH and GI using the section method and indicate whether each element is subjected to the effect of tensile or compressive forces. $($c$)$ Calculate the force in element HJ using the knot method and indicate whether it is subjected to tension or compression.