Two heavy spheres each of mass \(100\) kg and radius \(0.10\) m are placed \(1.0\) m apart on a horizontal table. What is the gravitational potential at the midpoint of the line joining the centres of the spheres?
1. \(2.67\times10^{-8}\) J kg-1
2. \(0\)
3. \(6.67\times10^{-9}\) J kg-1
4. \(3.71\times10^{-8}\) J kg-1