Part a)
At t = 0 the position of the object is given as

At t = 2

so displacement of the object is given as

so average speed is given as

Part b)
instantaneous speed is given by


now at t= 0

at t = 1


at t = 2

Part c)
Average acceleration is given as



Part d)
Now for instantaneous acceleration
As we know that

at t = 0

at t = 1

now we have

At t = 2 we have



<em>so above is the instantaneous accelerations</em>
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

Where,
r= radius
While centripetal acceleration is defined by

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

The same route you take is the distance traveled, that is




PART B)
With the radius is possible calculate he centripetal acceleration,



Therefore the radius of the curva that the plane follows in making the turn is 1098.17m with a centripetal acceleration of 
Stop and look to see if anything is coming