What is the speed of a 70kg rock after it has fallen freely for 1000m

Answer 1

v^2 = 2gs
Now plug in your numbers

Answer 2

d = 1/2 * a * t^2 ... t = √(2 d / a) = √(2 * 1000 / 9.8) ... seconds

the speed (velocity) of the rock is time multiplied by gravitational acceleration