$2.(30$ marks$)$ A particle with a mass of $\backslash ($ m $\backslash )$ is doing a circular motion with a constant speed of $\backslash ($ v $\backslash )$ on an inclined smooth surface $($neglect friction$).$ The radius of the circle is $\backslash ($ r $\backslash ).$ Derive the inclination angle $\backslash (\backslash$theta $\backslash ),$ which allows the particle to maintain this uniform circular motion.

P$.1$ of $4$