A Boeing 747 "Jumbo Jet" has a length of 55.9 m. The runway on which the plane lands intersects another runway. The width of the intersection is 24.0 m. The plane decelerates through the intersection at a rate of 5.61 m/s2 and clears it with a final speed of 43.3 m/s. How much time is needed for the plane to clear the intersection?(Note that the plane enters the intersection when any part of the plane is in the intersection and blocking the other runway. The plane clears the intersection when there is no longer any part of the plane in the intersection blocking the other runway.)

Answer 1

V = 43.3 m/s.
a = -5.61 m/s^2
d = 24 + 55.9 = 79.9 m.

V^2 = Vo^2 + 2a*d = 43.3^2
Vo^2 - 11.22*79.9 = 1874.9
Vo^2 = 1874.9 + 21036 = 22,911
Vo = 151.4 m/s. = Initial velocity.

V = Vo + a*t
V = 43.3 m/s.
Vo = 151.4 m/s.
a = -5.61 m/s^2
Solve for t.