1. The problem statement, all variables and given/known data Compare the gravitational force on a 9 kg mass at the surface of the Earth (with radius 6.4 × 10^6 m and mass 6 × 10^24 kg) with that on the surface of the Moon (with mass 1 /81.3 ME and radius 0.27 RE ). What is the force on the Earth? Answer in units of N. 2. Relevant equations I need to use this equation.... F(from 1 to 2)= G(m1m2/r^2) r(from 1- 2) 3. The attempt at a solution I know that G is a constant which equals 6.67 x 10^-11. I believe and m1 and m2 are the masses of earth and the object respectivly. I believe the r^2 is the radius of earth squared. im just not sure where r(from1-2) is i know that it is a vector. please help !