A potato is launched into the air at a velocity of 60 feet per second off of a building that is 210 feet tall. This can be modeled by the formula $\displaystyle{h}=-{16}{{t}}^{{2}}+{60}{t}+{210}\usepackage{cmbright}\Huge\$ , where h is the height (in feet) after t seconds. When will the potato hit the ground? (Round to the nearest second.)