1. The problem statement, all variables and given/known data A geologist searching for oil finds that the gravity at a certain location is 5 parts in 10^7 smaller than average. Assume that a deposit of oil is located 2000 meters directly below. Estimate the size of the deposit, assumed spherical. Take the density (mass per unit volume) of rock to be 3000 kg/m^3 and that of oil to be 800 kg/m^3. 2. Relevant equations g = F/m ...? 3. The attempt at a solution Usually when trying to do physics homework, I try to build the solution without following the book, or looking up equations, based on my understanding of how the concepts work out. My first thought was to find the radius of the oil deposit... however I could see no way to figure that out. My second thought, and my first approach, was to cube the distance, and turn it into a ratio problem. However several attempts an reattempts just did not seem to work. After a long while I did consult the book, which had no examples that I could see related to the problem. I did find one equation that seems like it could be applied to the situation, however I cannot seem to figure out how to apply it. This equation being g = F/m.