.
For this decelerated movement, the formula for the distance to get full stop is
S =
,
where S is the distance (in meters), "a" is acceleration (in m/s^2), t is time (in seconds).
Before applying this formula, you need to know the value of the acceleration (deceleration in this case). It is
a =
=
.
I gave you all necessary instructions - You make all necessary calculations.