Answer
$2.05$ seconds.
Work Step by Step
The given function is
$\Rightarrow h=-16t^2+30t+6$
At the ground $h=0\;feet$.
Substitute the value of $h$ into the function.
$\Rightarrow 0=-16t^2+30t+6$
Divide the equation by $2$.
$\Rightarrow 0=-8t^2+15t+3$
Use the quadratic formula to solve for $t$.
$t=\frac{-15\pm\sqrt{15^2-4(-8)(3)}}{2(-8)}$
Simplify.
$t=\frac{-15\pm\sqrt{225+96}}{-16}$
$t=\frac{-15\pm\sqrt{321}}{-16}$
$t=2.05$ (Rounded to two decimal places).
Hence, the time is $2.05$ seconds.
