Explanation

90km

$u = 90km/hr$

let's change to $m/s$

$= \frac {90 \times 10^3 }{3600}$ $= 25m/s$

$v = 0$ (brought to rest)

to find $a$ we use $v = u - at$

since $v = 0$

$0 = u - at$

$u = at$

and make $a$ the subject of the formula

$a = \frac {u}{t}$ $= 25 /10$ $= 2.5$

to get the distance we use

$v^2 = u^2 - 2as$

since v = 0

we have $s = \frac {u^2}{2a}$

s = $\frac {25^2}{2 \times 2.5}$ = 125m

90km

$u = 90km/hr$

let's change to $m/s$

$= \frac {90 \times 10^3 }{3600}$ $= 25m/s$

$v = 0$ (brought to rest)

to find $a$ we use $v = u - at$

since $v = 0$

$0 = u - at$

$u = at$

and make $a$ the subject of the formula

$a = \frac {u}{t}$ $= 25 /10$ $= 2.5$

to get the distance we use

$v^2 = u^2 - 2as$

since v = 0

we have $s = \frac {u^2}{2a}$

s = $\frac {25^2}{2 \times 2.5}$ = 125m