Example 3.2 First year physics Federal and KP Textbook equations of motion

A JF thunder 17 aircraft takes off at 70.0 m/s. After accelerating uniformly at 3.90 m/s² from rest that lasts 6.5 second during the initial phase of takeoff. The after burner engines are then turned up to full power for an acceleration of 7.1 m/s². Calculate the length of runway needed and the total time of takeoff.