A particle of mass \(m\), and angular momentum \(l\) is moving in a circular orbit of radius \(r_{0}\) under the influence of an attractive force \( \vec{F}(r) = - \dfrac{k}{r^{2}} \, \hat{r} \). Keeping its angular momentum unchanged, the particle is displaced radially by small distance \(\delta r \ll r_{0}\), due to which its radial distance varies periodically.
The corresponding time period is:
