12-22 할리데이 11판 솔루션 일반물리학

$$\put \begin{cases} A : \text{Top Ball}\\ B : \text{Bottom Ball}\\ L : \text{Left Wall}\\ R : \text{Right Wall}\\ G : \text{Ground}\\ \end{cases}$$ $$\begin{cases} \Sigma F_{Ax}&=0\\ \Sigma F_{Ay}&=0\\ \Sigma F_{Bx}&=0\\ \Sigma F_{By}&=0\\ \end{cases}$$ $$\begin{cases} 0&=N_{ABx}-N_R\\ 0&=N_{ABy}-mg\\ 0&=N_L-N_{ABx}\\ 0&=N_G-N_{ABy}-mg\\ \end{cases}$$ $$\theta=45\degree\Rarr N_{ABx}=N_{ABy}$$ $$\ab{a,b,c,d}$$ $$\begin{cases} N_G&=2mg\\ N_L&=mg\\ N_R&=mg\\ N_{AB}&=\sqrt2 mg \end{cases}$$