The truck and the tanker have weights of 8000 lb and 20 000 lb respectively. Their respe...

Free body diagram of the tanker:

Taking moment about D

$$ \begin{aligned} &\sum M_{D}=0 \\ &W_{2}(10)-N_{A}(25)=0 \\ &20000(10)-N_{A}(25)=0 \\ &25 N_{A}=200000 \\ &N_{A}=8000 \mathrm{lb} \end{aligned} $$

Resolving the forces along \(\mathrm{x}\)-direction

$$ \begin{aligned} &\sum F_{x}=0 \\ &D_{x}=0 \end{aligned} $$

Similarly, resolving the forces along \(y\)-direction

$$ \begin{aligned} &\sum F_{y}=0 \\ &N_{A}+D_{y}-W_{2}=0 \\ &N_{A}+D_{y}-20000=0 \\ &8000+D_{y}-20000=0 \\ &D_{y}=12000 \mathrm{lb} \end{aligned} $$

Free body diagram of the truck:

Taking moment about B

$$ \begin{aligned} &\sum M_{B}=0 \\ &N_{C}(14)-W_{1}(9)=0 \\ &N_{C}(14)-8000(9)=0 \\ &14 N_{C}=72000 \\ &N_{C}=5142.85 \mathrm{lb} \end{aligned} $$

Resolving the forces along \(y\)-direction

$$ \begin{aligned} &\sum F_{y}=0 \\ &N_{B}+N_{C}-D_{y}-W_{1}=0 \\ &N_{B}+5142.85-12000-8000=0 \\ &N_{B}=14857.15 \mathrm{lb} \end{aligned} $$

The reaction at \(\mathrm{A}\) is \(N_{A}=8000 \mathrm{lb}\)

The reaction at \(\mathrm{B}\) is \(N_{B}=14857.15 \mathrm{lb}\)

The reaction at \(\mathrm{C}\) is \(N_{C}=5142.85 \mathrm{lb}\)