An engineer at NASA is investigating the impact of meteorites on planets. He performs experiments in a vacuum by dropping metal spheres of different sizes and different heights above a horizontal bed of sand. In one experiment, a metal sphere of mass 0.1 kg is dropped from a height of 1.2 m. The sphere makes a depression in the sand of 2 cm. [Gravitational field strength, g = 10 Nkg -1 ] i) Calculate the potential energy of the sphere at a height of 1.2 m [2 marks] ii) Calculate the work done by the sphere as it comes to rest in the sand [2 marks].