posted by Jessica .
What is the gravitational potential energy of a two-particle system with masses 5.4 kg and 5.0 kg, if they are separated by 1.3 m? If you triple the separation between the particles, how much work is done (b) by the gravitational force between the particles and (c) by you?
Please help me. i figured out how to get part a but part b and c i am confused on.