A car slows down from 23 m/s to rest in a distance of 85 m. what was its acceleration, assmed constant

First calculate the time by using following equation:

d = (vi+vf) / 2 x t

where t = time

vi is the initial velocity = 23 m/s

vf is the final velocity = 0 m/s

and d is the distance covered = 85m

85 = (23 + 0) / 2 x t

t = 85/11.5 = 7.39s

Now use this equation to find acceleration:

a = (vf-vi) / t

a = 0 - 23 / 7.39

a = - 3.112 m/s²

so, the acceleration is 3.112 m/s ²