5-7 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} \vec F &= 12\ut{N}\\ m_2 &= 2.1\ut{kg}\\ \theta &=25\degree\\ m_1 &= 3.0\ut{kg}\\ g&=9.80665\ut{m/s^2} \end{cases} $$ $$\Sigma \vec F = m\vec a,$$ $$ \begin{cases} \Sigma \vec F_2 &= m_2\vec a\\ \Sigma \vec F_1 &= m_1\vec a\\ \end{cases} $$ $$ \begin{cases} F-T-m_2g\sin\theta &= m_2\vec a\\ T &= m_1\vec a\\ \end{cases} $$ $$ \begin{aligned} T&= \frac{3}{17} (40-7 g \sin25\degree)\\ &\approx 1.939184887853646\ut{N}\\ &\approx 1.9\ut{N}\\ \end{aligned} $$