an aeroplane travels 280m down the runway before taking off.if it start from rest , moves constant acceleration and becomes airbone in 8 second what is its speedin m/s,when it takes off

Answer 1

vf=at or vf=a*8

and..
vf^2=vi^2 + 2ad
vf^2=2a*280

so one has two equations..
vf=8a and
vf^2=560a

vf=8(vf^2/560) or

vf=560/16 check my math...