Answer
$14.07\space km$
Work Step by Step
Please see the attached image first.
Let's assume gravitational acceleration $(g) = 9.8\space m/s^{2}$
First of all, let's convert 988km/h into m/s by using 1000 m/km & 3600 s/h conversion factors as follows.
$988\space km/h=(\frac{988\space km}{h})(\frac{1000\space m}{km})(\frac{h}{3600\space s})= 274.4\space m/s$
We know that, $a=\frac{V^{2}}{r}$ in a circular motion
By using this equation we can find the turning radius of the jet plane as follows.
$a=\frac{V^{2}}{a}$
Now plug known values into this equation,
$r=\frac{(274.4\space m/s)^{2}}{0.564\times9.8\space m/s^{2}}$
$r= 14071.79\space m= 14.07\space km$
The minimum turning radius for the plane = 14.07 km
