1. The problem statement, all variables and given/known data An airplane maintains a constant acceleration of 4.0m/s^2 as it speeds up from 16m/s [E] to 28 m/s [E]. A what is the average velocity? b) how long does the airplane accelerate? c) when is the instantaneous velocity equal to the average velocity for the interval? a= 4.0 m/s^2 vi= 16m/s [E] vf= 28m/s[E] 2. Relevant equations 3. The attempt at a solution i found the answer to A and B Average velocity = 22 m/s. Total time = 3.0 s I don't know how instantaneous velocity is related to average velocity for the interval. Or how to find the answer. Someone help me?