Problem $3.$ For the truss shown below, use virtual work to compute the vertical displacement of joint

C for cases a$)$ and b$)$ below. Take $A=200m{m}^2$ and $E=200$GPa for each member. Assume that the

thermal expansion or misfit applies in addition to the indicated loads:

a$)$ Members AB and BC experience a temperature increase of $T=50C.$ Take $=12\frac{{10}^{-6}}{}C.$

Answer to check: ${}_c=39\mathrm{.}3mm($indicate direction$)$

b$)$ Member CD is fabricated $10$ mm too long. Answer to check: ${}_c=7\mathrm{.}3mm($indicate direction$)$