Problem $4$: induced drag $(25$ pts$).$ The Cessna Cardinal, a single$-$engine light plane, has a wing with an area of $\backslash (16\mathrm{.}2\backslash$mathrm$\{$~m$\}^\{2\}\backslash )$ and an aspect ratio of $7\mathrm{.}31.$ Assume that the span efficiency factor is $0\mathrm{.}62.$ If the airplane is flying at standard sea$-$level conditions with a velocity of $\backslash (251\backslash$mathrm$\{$~km$\}/\backslash$mathrm$\{$h$\}\backslash ),$

$($a$)(10$ pts$)$ What is the induced drag when the total weight is $9800$ N $?$

$($b$)(10$ pts$)$ Calculate the induced drag when the velocity is $\backslash (85\mathrm{.}5\backslash$mathrm$\{$~km$\}/\backslash$mathrm$\{$h$\}\backslash )($stalling speed at sea level with flaps down$).$

$($c$)(5$ pts$)$ Compare the results of $($a$)$ and $($b$).$ What observations can you make?