Problem $1$:

$($This is the same problem you solved in HW#$2.$ We'll solve it a different way in HW#$3.)$ The

rodABCD is made of an aluminum for which $E=70$GPa. For the loading shown, determine the

deflection of $(a)$ point $B,(b)$ point $D.$ In HW#$2$ you likely solved for deflection at $B$ and $D$ using

the following method:

$={\displaystyle \underset{i}{\overset{?}{}}}\frac{P_i{L}_i}{A_i{E}_i}$

In the real world $($i$.$e$.$ job$)$ wrong answers can be disastrous. We always need to check are results

$($units$,$ alternate solution, test, etc.$).$ If the problem can be solved in two different ways an

engineer should always do this as a check on their work. In this homework assignment solve the

problem using the linear superposition method discussed in class. $($Hint: For deflection at point

D$,$ the $50$ kN load contribution also requires that we combine mechanical springs in series or in

parallel.$)$

Ans:

$0\mathrm{.}781$mmdarr

$=5\mathrm{.}71$mmdarr