Required information

Problem $04\mathrm{.}115-$ Supported platform

In the given figure, the horizontal platform $\backslash ($ A B C D $\backslash )$ weighs $\backslash (60-\backslash$mathrm$\{$lb$\}\backslash )$ and supports a $\backslash (300-\backslash$mathrm$\{$lb$\}\backslash )$ load at its center. The platform is normally held in position by the hinges at $\backslash ($ A $\backslash )$ and $\backslash ($ B $\backslash )$ and by braces $\backslash ($ C E $\backslash )$ and $\backslash ($ D E $\backslash ).$ Consider brace $\backslash ($ D E $\backslash )$ is removed. The hinge at $\backslash ($ A $\backslash )$ does not exert any axial thrust.

Problem $04\mathrm{.}115.$b $-$ Reaction forces at the hinges

Determine the reactions at hinges and the force exerted by the remaining brace $\backslash ($ C E $\backslash ).($Include a minus sign if necessary.$)$

The force exerted by the brace CE is

The reaction at $\backslash ($ A $\backslash )$ is $($

lb$)$ i$.$

The reaction at $\backslash ($ B $\backslash )$ is $($

lb$)\backslash (\backslash$mathbf$\{$i$\}+(\backslash )$

lb$)\backslash (\backslash$mathbf$\{$j$\}+(\backslash )$

lb$)\backslash (\backslash$mathbf$\{$k$\}\backslash ).$