Problem $3$

Use the virtual work method to determine $($a$)$ the

horizontal displacement at Joint B and $($b$)$ the

vertical displacement at Joint $C.$

Note: $E=29,000$ksi for all members; Bar areas

are as follows: $A_{AB}=7i{n}^2,A_{BC}=A_{DE}=A_{EC}=$

$2i{n}^2,A_{AD}=A_{BE}=4i{n}^2,$ and $A_{DB}=6i{n}^2$