Answer
The acceleration is 8.75 m/s^{2}
Work Step by Step
The initial speed of a plane is 300 m/s
Distance covered by plane is 4 km or 4000 m
The final speed of the plane is 400 m/s
Use kinematical equation V(final)^{2} = V(initial)^{2} + 2ad
Substitute known values
(400 m/s)^{2} = (300 m/s)^{2} + 2a(4000 m)
(400 m/s)^{2} - (300 m/s)^{2} = (8000m)a
7000 m/s^{2}/8000m = a
Therefore, the acceleration of the plane is 8.75 m/s^{2}.
