An airplane travels 280m down the runway before taking off. If it starts from rest,moves with constant acceleration

acceleration
constant

#1

An airplane travels 280m down the runway before taking off. If it starts from rest,moves with constant acceleration,and becomes airbone in 8.00s, what is its speed, in m/s, when it takes off?

Answer:

the average speed is … 280 m / 8.00 s = 35 m/s

the initial speed is zero (rest), so the final speed (take off) is
… ave = (init + fin) / 2 … 35 = (0 + f) / 2 … f = 70 m/s