1. The problem statement, all variables and given/known data Suppose the mass of the Earth were doubled , but it kept the same density and spherical shape. How would the weight of objects at the Earh's surface change? 2. Relevant equations Fg=Gm1m2/r^2 3. The attempt at a solution g=G2m/r^2 g=19.59817612 g/g(on earth - 9.8) =2 I know this is wrong because the textbook says the answer is 1.26 or 2^1/3. I have no idea how to get this answer. I did find an online solution but they used equations that I have not been taught. Here is a link to the online solution: http://archives.evergreen.edu/webpages/curricular/2005-2006/PhyAstro/0506/HW/G6solns.pdf If anyone can explain how to get this answer step by step that would be great.