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) $\sqrt { \frac { 2 G } { R ^ { 3 } } }$

Four particles each of mass $M$, move along a circle of radius $R$ under the action of their mutual gravitational attraction as shown in figure. The speed of each particle is:
(1) $\frac { 1 } { 2 } \sqrt { \frac { G M } { R } (2 \sqrt { 2 } + 1)}$
(2) $\frac { 1 } { 2 } \sqrt { \frac { G M } { R ( 2 \sqrt { 2 } + 1 ) } }$
(3) $\frac { 1 } { 2 } \sqrt { \frac { G M } { R } (2 \sqrt { 2 } - 1)}$
(4) $\sqrt { \frac { G M } { R } }$