Question

A Boeing 747 "Jumbo Jet" has a length of 59.7 m. The runway on which the plane lands intersects another runway. The width of the intersection is 25.0 m. The plane decelerates through the intersection at a rate of 5.4 m/s2 and clears it with a final speed of 53 m/s. How much time is needed for the plane to clear the intersection?

Answer 1

t = 1.48 s

Step-by-step explanation:

As we know that length of the Boeing plane is

`L = 59.7 m`

width of the intersection is given as

`w = 25.0 m`

now we know that deceleration of the plane is given as

`a = -5.4 m/s^2`

Also the final speed of the plane while it clears the intersection is given as

`v_f = 53 m/s`

now we have

`d = ((v_f + v_i)/(2)) t`

`(25 + 59.7) = ((53 + v_i)/(2)) t`

also we know that

`v_f - v_i = at`

`53 - v_i = -5.4 t`

now we have

`84.7 = ((53 + 53 + 5.4t)/(2))t`

by solving above equation we have

`t = 1.48 s`