# A car travelling on a straight road at $15.0$ meter per second accelerates uniformly to a speed of $21.0$ meters per second in $12.0 \;second$. The total distance traveled by the car in this $12.0$ second time interval is

$\begin{array}{1 1} 36.0\;m \\ 180\;m \\ 216\;m \\252\;m \end{array}$

Given $v_i =15 m/s$
$v_j =21 m/s$
$t=12 s$
Can't find d directly , find a first
$v_f =v_i +at$
$a= \large\frac{v_f-v_i}{t}$
Now solved for d
$d= v_i t +\large\frac{1}{2} $$at^2 d= \large\frac{1}{2}$$(12s) (15 m/s+21 m/s)$
$d=216\;m$