Given: Consider the truss shown below with the loading on joints D$,$ K$,$ S and U$.$

Find: For this problem:

a$)$ Identify all zero$-$force members in the truss.

b$)$ Determine the external reactions acting on the truss at supports A and B$.$

c$)$ Determine the load carried by members RS and DS$.$ Identify each member as either being in tension, in compression or carrying zero load.

For this problem, use the following parameters: $h=1\mathrm{.}2m,b=1\mathrm{.}6m,F=12$ksi,$P=36$ ksi and $Q=24$ ksi.