A spherically symmetric gravitational system of particles has a mass density $$\rho = \left\{ {\begin{matrix} {{\rho _0}} & {for} & {r \le R} \\ 0 & {for} & {r \gt R} \\ \end{matrix} } \right.$$ Where $\rho_0$ is a constant. A test mass can undergo circular motion under the influence of the gravitational field of particles. Its speed V as a function of distance $r(0 \lt r \lt \infty)$ from the centre of the system is represented by