The Mars rover drops a rock off the rim of a 120 meter high cliff on Mars. The free-fall acceleration is -3.7m/s2. What is the velocity that the rock hits the ground?

Answer 1

as on earth
v^2 = 2as = 2(3.7)(120)
v = -27.8 m/s
Note that you kind of have to fudge on the negative sign to take the square root, then apply it again at the end.