9-54 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} m_A&=3.18\times10^4\ut{kg}\\ v_{Bi}&=0\\ \end{cases} $$ $$ \begin{cases} \Delta \Sigma \vec p&=0\\ \Delta \KE&=1-\frac{27}{100} \end{cases} $$ $$ \begin{cases} m_Av_i&=(m_A+m_B)v_f\\ \frac{73}{100}\cdot\frac{1}{2}m_A{v_{i}}^2&=\frac{1}{2}(m_A+m_B){v_{f}}^2 \end{cases} $$ $$ \begin{aligned} m_B&= \frac{27}{73}m_A \\ &=\frac{4293}{3650}\times10^4\ut{kg}\\ &\approx 1.1761643835616438\times10^4\ut{kg}\\ &\approx 1.18\times10^4\ut{kg}\\ &\approx 11.8\ut{ton}\\ \end{aligned} $$