Answer
$1.6$ seconds.
Work Step by Step
The given function is
$\Rightarrow h=-16t^2+40$
Substitute the value of $h$ into the function.
$\Rightarrow 0=-16t^2+40$
Subtract $40$ from both sides.
$\Rightarrow 0-40=-16t^2+40-40$
Simplify.
$\Rightarrow -40=-16t^2$
Divide both sides by $-16$.
$\Rightarrow \frac{-40}{-16}=\frac{-16t^2}{-16}$
Simplify.
$\Rightarrow 2.5=t^2$
Take the square root on both sides.
$\Rightarrow 1.6=t^2$.
Hence, the orange hit the water in $1.6$ seconds.
