A little green moon person stands by the rim of a crater on the Moon, where
the freefall acceleration is 1.62 m/s2 and there is no air resistance. The crater
has vertical walls. To determine the depth of the crater, she drops a rock and
measures the time it takes for it to hit the bottom. If the depth of the crater is
120 m, after what time interval will the rock hit the floor of the crater?
