I'm a newbie to this subject, so forgive me if what I'm asking supposed to be common sense. An airplane travels 280 m down the runway before taking off. If it starts from rest, moves with a constant acceleration, and becomes airborne in 8.00 s, what is its speed in m/s, when it takes off? So, I think what is given is d=280m then t=8.00s and it is implied that it's initial velocity is 0. And what is asked is the speed or velocity... Here's the thing. My friend keeps telling me that I should find first acceleration before speed, but I keep saying that I can simply just use d/s. Then, that conversation left me confused. So, what formula should I really use?