Question

We investigated a jet landing on an aircraft carrier. In a later maneuver, the jet comes in for a landing on solid ground with a speed of 90 m/s, and its acceleration can have a maximum magnitude of 7.32 m/s² as it comes to rest.

(a) From the instant the jet touches the runway, what is the minimum time interval needed before it can come to rest?
s

(b) Can this jet land on a small tropical island airport where the runway is 0.800 km long?

YesNo    

(c) Explain your answer.

Answer 1

(a) Speed of the jet, u = 90 m/s

maximum acceleration of the jet, a = 7.32 m/s^2

when the jet comes at rest, speed = 0

use the expression -

v = u + a*t

=> 0 = 90 - 7.32*t (we have taken negative sign of the acceleration because it is retarding acceleration)

=> t = 90 / 7.32 = 12.3 s.

(b) distance travelled by the jet in this slot of time -

d = v^2 / (2*a) = 90^2 / (2*7.32) = 553.3 m

This distance is lower than the runway length which is 0.800 km = 800 m

So, the jet can land on the small tropical island.

(c) I think I have already explained the answer above.