1. The problem statement, all variables and given/known data There are two masses of unknown weight on a straight line with a small red particle between them. At x (Measured from the center of m1) = .515 the particle does not move. What is the ratio of the two masses? i.e. m2/m1. 2. Relevant equations 3. The attempt at a solution So do I use F = G*m1*m2/r^2? Since the particle isn't moving then the forces are balanced does this mean F = 0 then?