Two particles each of mass 'm' are placed at `A` and `C` are such `AB=BC=L`. The gravitational force on the third particle placed at `D` at a distance `L` on the perpendicular bisector of the line `AC` is

Three points A , B and C each of mass m is placed in a line with AB=BC=d. Find the gravitational force on a fourth particle P of the same mass placed at a distance d from particle B on the perpendicular bisector of the line AC.

Three points A , B and C each of mass m is placed in a line with AB=BC=d. Find the gravitational force on a fourth particle P of the same mass placed at a distance d from particle B on the perpendicular bisector of the line AC.

Three portion A , B and C each of mass re placed ina line with AB=BC=d. Find the gravittional force on a fourth article P of same mass placed at a distance d from the particle B on the perpendicular bisector of the line AC.

Four particles each of mass m are placed at the vertices of a square of side l. the potential at the centre of square is

Four particles each of mass m are placed at the vertices of a square of side l. the potential at the centre of square is

Three particles each of mass m are kept at vertices of an equilateral triangle of side L. The gravitational field at centre due to these particle is