Answer:
Centripetal acceleration,

Explanation:
Centripetal acceleration:
Centripetal acceleration is the idea that any object moving in a circle, in something called circular motion, will have an acceleration vector pointed towards the center of that circle.
Centripetal means towards the center.
Examples of centripetal acceleration (acceleration pointing towards the center of rotation) include such situations as cars moving on the cicular part of the road.
An acceleration is a change in velocity.
Formula for Centripetal acceleration:

Given here,
Velocity = 4.5 m/s
radius = 7.7 m
To Find :

Solution:
We have,

Substituting given value in it we get

Centripetal acceleration,

Answer:
a) 6076 m
b) 43.33 m/s
c) 68 m/s
Explanation:
(a) If the airplane rounds half the circle in 156s, its displacement is the circle diameter in 156s, or twice the circle's radius
s = 2r = 2* 3.38km = 6.76 km or 6760 m
(b) The average velocity would be displacement over unit of time
v = s/t = 6760 / 156 = 43.33 m/s
(c) The length of the chord it's swept in 156s is half of the circle perimeter
c = πr = π3.38 = 10.62 km or 10620 m
The airplane average speed is its chord length over a unit of time
c / t = c / 156 = 68 m/s
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I hope this helps!
~cupcake