Answer to Question #241975 in Physics for Kristine

Question

An airplane requires a speed of 80 𝑚𝑖/ℎ𝑟 to be airborne. It starts from rest on a runway 1600 𝑓𝑡 long. a) What must be the minimum safe acceleration of the airplane? b) With this acceleration, how many seconds will it take for the plane to acquire its needed speed for take-off?

Answer 1

Given:

$v=80\:\rm mi/h=35.8\: m/s$

$d=1600\:\rm ft=488\: m$

(a) the minimum safe acceleration of the airplane

$$a=\frac{v^2}{2d}=\frac{35.8^2}{2*488}=1.31\:\rm m/s^2=4.30\: ft/s^2$$

(b) the time of runway motion

$$t=\frac{v}{a}=\frac{35.8}{1.31}=27.3\:\rm s$$