Question

An aeroplane lands at 216 kmh⁻¹ and stops after covering a runway of 2 m. Calculate the acceleration and the time, in which it comes to rest.

Answer 1

Initial velocity = u = 216 kmh⁻¹

u = `216xx5/18` = 60 ms⁻¹

Final velocity = v = 0

Distance = S = 2 km = 2000 m

v² − u² = 2aS
(0)² − (60)² = 2a (2000)
4000 a = −3600
(Acceleration) a = `(-3600)/4000`
= −0.9 ms⁻²
Now, v = u + at
0 = 60 + (−0.9)t
0.9t = 60
(Time) t = `60/0.9=600/9` = 66.67 S