$[\left.g =10\,m / s ^{2}\right]$
\(mg 2 R =\frac{\omega^{2}}{2}\left[\frac{ mR ^{2}}{2}+ mR ^{2}\right]\)
\(mg 2 R =\frac{\omega^{2}}{2} \frac{3}{2} mR ^{2}\)
\(\frac{3}{4} \omega^{2}=\frac{2 g }{ R }\)
\(\omega^{2}=\frac{8 g }{3 R }\)
\(\omega=\sqrt{\frac{80}{3 R}}\)
\(16 \frac{ x }{3 R }=\frac{80}{3 R }\)
\(x =5\)