The floor of the basement of a house is 2.5m below ground level, and the floor of the attic is 4.4m above ground level.
1. What are the respective potential energies of 2.8kg objects in the basement and attic, relative to ground level? Express the answer with two important figures, separated by commas.
2. What is the change in potential energy if the object in the attic is brought to the basement?