Two point-lie objects, each with mass m, are connected by a massless rope of length l. The objects are suspened vertically near the surface of Earth, so that one object is hanging below the other. Then the objects are released. How can I find the tension in the rope? I know there 3 force, tension, Graviational Froce on each block. but how can I set them up? my first thought was (M*m*G)/(R^2)+(M*m*G)/((R+l)^2)-T-(m*m*G)/(l^2)=(2m)G/(R^2). I know it's wrong but I don't know where's my mistake.