physics
posted by Karen .
A Boeing 787 is initially moving down the runway at 3.0 m/s preparing for takeoff. The pilot pulls on the throttle so that the engines give the plane a constant acceleration of 1.7 m/s2. The plane then travels a distance of 1900 m down the runway before lifting off. How long does it take from the application of the acceleration until the plane lifts off, becoming airborne?

d = Vo*t + 0.5a*t^2 = 1900 m.
3t + 0.5*1.7*t^2 = 1900
0.85t^2 + 3t  1900 = 0
t = 45s.(Use Quadratic Formula).