Answer
$t = 14~s$
Work Step by Step
We can find the required angle:
$\theta~r = x$
$\theta = \frac{x}{r}$
$\theta = \frac{5.6~m}{0.040~m}$
$\theta = 140~rad$
We can find the required time $t$:
$\theta = \frac{1}{2}\alpha~t^2$
$t^2 = \frac{2\theta}{\alpha}$
$t = \sqrt{\frac{2\theta}{\alpha}}$
$t = \sqrt{\frac{(2)(140~rad)}{1.5~rad/s^2}}$
$t = 14~s$
