\(\displaystyle{o}{v}{e}{r}\rightarrow{\left\lbrace{F}\right\rbrace}={800}\ {l}{b}\ {\left[-{\frac{{{2}}}{{\sqrt{{{3}}}}}}{w}{i}{d}{e}\hat{{{i}}}+{\frac{{{1}}}{{\sqrt{{{3}}}}}}{w}{i}{d}{e}\hat{{{i}}}\right]}\)

a) Point O

\(\displaystyle\Rightarrow{o}{v}{e}{r}\rightarrow{\left\lbrace{O}{A}\right\rbrace}={3}{j}\)

\(\displaystyle\therefore{o}{v}{e}{r}\rightarrow{\left\lbrace{C}\right\rbrace}={o}{v}{e}{r}\rightarrow{\left\lbrace{O}{A}\right\rbrace}\times{o}{v}{e}{r}\rightarrow{\left\lbrace{F}\right\rbrace}\)

\(\displaystyle={3}{j}\times{800}\ {l}{b}\ {\left[-{\frac{{{2}}}{{\sqrt{{{3}}}}}}{w}{i}{d}{e}\hat{{{i}}}+{\frac{{{1}}}{{\sqrt{{{3}}}}}}{w}{i}{d}{e}\hat{{{i}}}\right]}\)

\(\displaystyle={2771}\cdot{28}{w}{i}{d}{e}\hat{{{k}}}\ {l}{b}-{f}{t}\)

b) Point B \(\displaystyle\Rightarrow{o}{v}{e}{r}\rightarrow{\left\lbrace{B}{A}\right\rbrace}={4}{i}+{3}{w}{i}{d}{e}\hat{{{j}}}\)

\(\displaystyle\therefore{o}{v}{e}{r}\rightarrow{\left\lbrace{C}\right\rbrace}={o}{v}{e}{r}\rightarrow{\left\lbrace{B}{A}\right\rbrace}\times{o}{v}{e}{r}\rightarrow{\left\lbrace{F}\right\rbrace}\)

\(\displaystyle={\left({4}{w}{i}{d}{e}\hat{{{i}}}+{3}{w}{i}{d}{e}\hat{{{j}}}\right)}\times{800}\ {l}{b}{\left[-{\frac{{{2}}}{{\sqrt{{{3}}}}}}{w}{i}{d}{e}\hat{{{i}}}+{\frac{{{1}}}{{\sqrt{{{3}}}}}}{w}{i}{d}{e}\hat{{{i}}}\right]}\)

\(\displaystyle={4618}\cdot{8}{w}{i}{d}{e}\hat{{{k}}}\ {l}{b}-{f}{t}\)

a) Point O

\(\displaystyle\Rightarrow{o}{v}{e}{r}\rightarrow{\left\lbrace{O}{A}\right\rbrace}={3}{j}\)

\(\displaystyle\therefore{o}{v}{e}{r}\rightarrow{\left\lbrace{C}\right\rbrace}={o}{v}{e}{r}\rightarrow{\left\lbrace{O}{A}\right\rbrace}\times{o}{v}{e}{r}\rightarrow{\left\lbrace{F}\right\rbrace}\)

\(\displaystyle={3}{j}\times{800}\ {l}{b}\ {\left[-{\frac{{{2}}}{{\sqrt{{{3}}}}}}{w}{i}{d}{e}\hat{{{i}}}+{\frac{{{1}}}{{\sqrt{{{3}}}}}}{w}{i}{d}{e}\hat{{{i}}}\right]}\)

\(\displaystyle={2771}\cdot{28}{w}{i}{d}{e}\hat{{{k}}}\ {l}{b}-{f}{t}\)

b) Point B \(\displaystyle\Rightarrow{o}{v}{e}{r}\rightarrow{\left\lbrace{B}{A}\right\rbrace}={4}{i}+{3}{w}{i}{d}{e}\hat{{{j}}}\)

\(\displaystyle\therefore{o}{v}{e}{r}\rightarrow{\left\lbrace{C}\right\rbrace}={o}{v}{e}{r}\rightarrow{\left\lbrace{B}{A}\right\rbrace}\times{o}{v}{e}{r}\rightarrow{\left\lbrace{F}\right\rbrace}\)

\(\displaystyle={\left({4}{w}{i}{d}{e}\hat{{{i}}}+{3}{w}{i}{d}{e}\hat{{{j}}}\right)}\times{800}\ {l}{b}{\left[-{\frac{{{2}}}{{\sqrt{{{3}}}}}}{w}{i}{d}{e}\hat{{{i}}}+{\frac{{{1}}}{{\sqrt{{{3}}}}}}{w}{i}{d}{e}\hat{{{i}}}\right]}\)

\(\displaystyle={4618}\cdot{8}{w}{i}{d}{e}\hat{{{k}}}\ {l}{b}-{f}{t}\)