Find the intensity of gravitational field at a point lying at a distance `x` from the centre on the axis of a ring of radius `a` and mass `M`.

Explanation

Consider any particle of mass dm Gravitational filed at point `P` due to dm
`dE = (Gdm)/(r^(2))` along `PA`
Component along `PO` is
`dE cos theta = (Gdm)/(r^(2)) cos theta`
Net gravitational filed at point `P` is
`E=int(Gdm)/r_(2)costheta=(Gcostheta)/(r^(2))intdm=(GMr)/((R^2+x^(2))^(3//2))` towards the centre of ring
.