An aircraft lands on a runway at a speed of 40ms-1 and brakes to a halt in a distance of 860m?

Question

a) Calculate the braking time

b) Calculate the deceleration of the aircraft

AS Physics questions, thanks.

Answer 1

a)

Because the movement is in the horizontal direction you can just use t = d/v

t = d/v

= 860/40

= 21.5 seconds

b) a = (v-u)/t

When it stops its final speed will be 0 ms^-1

So

a = (v-u)t

= (0-40)/21.5

= -1.86 ms^-2

Answer 2

a = -v0^2/(2x) = -0.93023 m/s^2
t = x/v(avg) = 2x/(v0+v1) = 43 s
EDIT: Other answers say time = distance/initial velocity. Not so; it's distance/average velocity. It is distance/initial velocity only if velocity remains constant.

Answer 3

a)time=distance/speed
t=860m/40ms-1
t=21.5sec

b)deceresion= (final-initial velocity)/time
de=(0-860)/21.5
de=-40ms-1