At a dock, a crane lifts a 1200 kg container 30 m, swings it out over the deck of a frieghter, and lowers the container into the hold of the freighter, which is 10 m below the level of the dock. The acceleration of gravity is 9.8 m/s2. Neglect friction losses. How much work is done by the crane on the container? Answer in units of kJ.