Because acceleration is constant, the acceleration of the car at any time is the same as its average acceleration over the duration. So

Now, we have that

so we end up with a distance traveled of


Because force always has a direction, it always works towards or against something.
you might know that force,
is rate of change of momentum i.e
force = m (v-u)/t
= (mv - mu )/ t
as we know momentum is a vector quantity so, the rate of change of momentum i.e Force would also be a vector quantity.
momentum = mass × velocity
velocity has a direction so,
momentum has also got a direction.
so, momentum is also a vector quantity.