1. The problem statement, all variables and given/known data X & Y are two points at respective distances R and 2R from the centre of the Earth, where R is greater than the radius of the Earth. The gravitational potential at X is -800kJkg^-1. When a 1kg mass is taken from X to Y, what is the work done on the mass? 2. Relevant equations Gravitational Potential = -GM/r U= -GMm/r 3. The attempt at a solution I have thought over this question and tried using integration to make sense of it since gravitational potential and U varies w/ r. But when I tried thinking along the lines of integration, I find myself wondering what does the integrated value of graph U against r represent as it does not concur with what I am trying to find with regards to the concept of homogeneity. Is my idea of trying to integrate wrong? Or is my concept wrong to begin with? Please help, thank you.