The figure depicts a simple truss with external loads applied at joints B$,$ H$,$ and L$.$ The horizontal and vertical members are of equal length $(2$ m $).$ The truss is pin supported at A and roller supported at M$.$

$AC=2m$;$W_1=10kN$;$W_2=10kN$;$W_3=30kN$

a$)$ Identify zero$-$force members.

b$)$ Calculate forces on members $JK$ and $JL$ using the method of sections and indicate whether they are in tension or compression $($zero points if the method of joints is used$).$

c$)$ Calculate forces on members KL and $LM$ using the method of joints and indicate whether they are in tension or compression $($zero points if the method of sections is used$).$