To solve for the time an object takes to hit the ground, the equation
<em>y</em> <em>= y₀ + v₀t + ½gt²</em>, or just <em>0 = y₀ +½gt²</em> since there is no initial velocity and the final y position is 0 (since it is on the ground). Therefore, <em>t = (−2y₀/g)^½.</em>
