Question $3(35$ Points$)$

Members $AB$ and BCDE are axially rigid frame members connected with an internal hinge at $B,$ and $BC$ is a truss member. $EI$ for $AB$ and BCDE are given as $1000kN.m^2.$ There is a clockwise couple moment at $D(10kN.m),$ an unknown downward force at $C(P),$ and a distributed load $(1.k\frac{N}{m})$ on $AB.$ The downward deflections at $B$ and $C$ are measured as $0\mathrm{.}01m$ and $0\mathrm{.}02m,$ respectively, as shown in the figure.

Calculate $($hint: in the listed order$)$

a$)$ Rotation at D$.(15$ points$)$

b$)$ EA$\text{'}$ of the truss member. $(10$ points$)$

c$)$ External load $P$ acting at C$.(10$ points$)$