$3\mathrm{.}4$ #$4.$ The equation for free fall at the surface of some planet $($ s in meters, t in seconds$)$ is $s=11\mathrm{.}24t^2.$ How long does it take a rock falling from rest to reach a velocity of $25\mathrm{.}4\frac{m}{s}$ on this planet?

It takes $$ sec for a rock falling from rest to reach a velocity of $25\mathrm{.}4\frac{m}{s}.$

$($Round to the nearest tenth as needed.$)$