$4\mathrm{.}43$ Consider a square flat plate at zero

incidence angle to a low$-$speed incompressible

flow. The length of each side is $4$ m $.$ Assume that

the transition Reynolds number is $5{10}^5$ and

that the free$-$stream properties are those at

standard sea level. Calculate the friction drag on

the flat plate when the free$-$stream velocity is $($a$)$

$20\frac{m}{s}$ and when it is $($b$)40\frac{m}{s}.($c$)$ Assuming

that the friction drag, $D_f$ varies with velocity as

$V_{}^n,$ calculate the value of the exponent $n$ based

on the answers from $($a$)$ and $($b$).$ How close does

ncome to $2?$