Answer :
To solve this exercise it is necessary to apply the concepts related to Centripetal and Perimeter acceleration of a circle.
The perimeter of a circle is defined by
[tex]P = 2\pi r[/tex]
Where,
r= radius
While centripetal acceleration is defined by
[tex]a=\frac{v^2}{r}[/tex]
Where,
v= velocity
r= radius
PART A)
The distance of a body can be defined based on the speed and the time traveled, that is
x = v*t
For our values the distance is equal to
x = 15*115=1725m
The plane when going to make the turn from east to south makes a quarter of the circumference that is
[tex]\frac{P}{4} = \frac{2\pi r}{4}[/tex]
The same route you take is the distance traveled, that is
[tex]x = \frac{P}{4}[/tex]
[tex]x = \frac{2\pi r}{4}[/tex]
[tex]1725 = \frac{2\pi r}{4}[/tex]
[tex]r = 1098.17m[/tex]
PART B)
With the radius is possible calculate he centripetal acceleration,
[tex]a = \frac{v^2}{r}[/tex]
[tex]a = \frac{115^2}{1098.17}[/tex]
[tex]a = 12.04m/s^2[/tex]
Therefore the radius of the curva that the plane follows in making the turn is 1098.17m with a centripetal acceleration of [tex]12.04m/s^2[/tex]