6-54 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} 1:\text{Eagle}\\ 2:\text{Fast} \end{cases} $$ $$ \begin{cases} v_1&=150\ut{km/h}\\ v_2&=320\ut{km/h} \end{cases} $$ $$D=\frac{1}{2}C\rho Av^2,$$ $$ \begin{cases} mg=\cfrac{1}{2}C\rho A_1{v_1}^2\\ mg=\cfrac{1}{2}C\rho A_2{v_2}^2\\ \end{cases} $$ $$ \begin{aligned} \frac{mg}{mg}&=\frac{\frac{1}{2}C\rho A_1{v_1}^2}{\frac{1}{2}C\rho A_2{v_2}^2}\\ 1&=\frac{A_1{v_1}^2}{A_2{v_2}^2}\\ \frac{A_1}{A_2}&=\(\frac{v_2}{v_1}\)^2\\ &=\frac{1024}{225}\\ \end{aligned} $$ $$A_1:A_2=1024:225$$