5-1 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} m_1 &= 10\ut{kg}\\ m_3 &= 15\ut{kg}\\ m_4 &= 22\ut{kg}\\ \end{cases} $$ $$ \begin{cases} T_2 &= 130\ut{N}\\ T_4 &= 222\ut{N}\\ \end{cases} $$ $$\Sigma \vec F = m\vec a,$$ $$ \begin{cases} \Sigma \vec F_1 = m_1\vec a\\ \Sigma \vec F_2 = m_2\vec a\\ \Sigma \vec F_3 = m_3\vec a\\ \Sigma \vec F_4 = m_4\vec a\\ \end{cases} $$ $$ \begin{cases} T_1 = m_1a\\ T_2-T_1 = m_2a\\ T_3-T_2 = m_3a\\ T_4-T_3 = m_4a\\ \end{cases} $$ $$ \begin{aligned} m_2 &= \frac{1945}{46}\ut{kg}\\ &\approx 42.28260869565217\ut{kg}\\ &\approx 42\ut{kg}\\ \end{aligned} $$