Answer
Time $=3.5$ seconds.
Work Step by Step
The equation is
$\Rightarrow d=\frac{1}{2}at^2$
The given values are
Acceleration $a=2\;ft/s^2$.
Distance $d=12\;ft$.
Substitute all values into the equation.
$\Rightarrow 12\;ft=\frac{1}{2}(2\;ft/s^2)(t)^2$
Simplify.
$\Rightarrow 12\;s^2=t^2$
Take the square root on both sides.
$\Rightarrow \sqrt{12\;s^2}=\sqrt{t^2}$
Simplify.
$\Rightarrow 3.5\;s=t$
