Answer
It takes 8.25 seconds for the object to reach the ground from the window washer.
Work Step by Step
For $h = -16t^2 + 1089$, $h$ is to be measured from the ground up and when the object reaches the ground, $h = 0$.
Therefore,
$0 = -16t^2 + 1089$
$16t^2 = 1089$
$t^2 = 68.0625$
$t = \pm 8.25$
$t = 8.25$ or $t = - 8.25$ (rejected)
Thus, it takes 8.25 seconds for the object to reach the ground from the window washer.
