Two identical particles of mass 1 kg each go round a circle of radius $R$, under the action of their mutual gravitational attraction. The angular speed of each particle is:\\
(1) $\sqrt { \frac { G } { 2 R ^ { 3 } } }$\\
(2) $\frac { 1 } { 2 } \sqrt { \frac { G } { R ^ { 3 } } }$\\
(3) $\frac { 1 } { 2 R } \sqrt { \frac { 1 } { G } }$\\
(4) $\sqrt { \frac { 2 G } { R ^ { 3 } } }$