An Airplane Makes a Gradual Turn While Flying at a Constant

Multiple Choice

An airplane makes a gradual 90 turn while flying at a constant speed of 200 m/s. The process takes 20.0 seconds to complete. For this turn the magnitude of the average acceleration of the plane is:

A) zero
B) 40 m/s²
C) 20 m/s²
D) 14 m/s²
E) 10 m/s²