એક શંકુમાં કણ 0.5 m/sec ની ઝડપથી વર્તુળમય

The particle is moving in circular path

From the figure, $mg = R\sin \theta $ …$(i)$

$\;\frac{{m{v^2}}}{r} = R\cos \theta $ …$(ii)$

From equation $(i)$ and $(ii)$ we get

$\tan \theta = \frac{{rg}}{{{v^2}}}$  but $\tan \theta = \frac{r}{h}$

$h = \frac{{{v^2}}}{g} = \frac{{{{(0.5)}^2}}}{{10}} = 0.025m = 2.5\,cm$