12-27 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} \theta&=36.9\degree\\ \phi&=53.1\degree\\ L&=4.35\ut{m}\\ \end{cases} $$ $$L=x+y,$$ $$ \begin{cases} \Sigma F_{x}&=0\\ \Sigma F_{y}&=0\\ \Sigma \tau&=0\\ \end{cases} $$ $$ \begin{cases} 0&=-T_1\sin\theta+T_2\sin\phi\\ 0&=T_1\cos\theta+T_2\cos\phi-mg\\ 0&=-xT_1\cos\theta+yT_2\cos\phi\\ \end{cases} $$ $$ \begin{aligned} x&={\cos\phi\sin\theta\over\sin\br{\theta+\phi}}L\\ &=L \sin ^236.9\degree\\ &\approx 1.568194344364676\ut{m}\\ &\approx 1.57\ut{m}\\ \end{aligned} $$