A ball of copper is dropped from height on an unknown planet....?

....the radius of the ball is 4.82 cm and it has a density of 8.94*10^3 kg m^3. After it has fallen 4.02 m it has a kinetic energy of 30.2 J and after 6.82 m it has kinetic energy of 46.8 J. What is the acceleration due to gravity on the unknown planet?