Standing on the surface of a small spherical moon whose radius is 6.00*104 m and whose mass is 7.50*1018 kg, an astronaut throws a rock of mass 2.05 kg straight upward with an initial speed 38.5 m/s. (This moon is too small to have an atmosphere.) What maximum height above the surface of the moon will the rock reach?
The Attempt at a Solution
I calculated g, then used the kinematic equation Δy = (vf2 - vi2) / 2a, but it didn't work! Did I use the wrong equations?