Question
A particle of mass m is under the influence of the gravitational field of a body of mass M( m). The particle is moving in a circular orbit of radius r_0 with time period T_0 around the mass M. Then, the particle is subjected to an additional central force, corresponding to the potential energy V_ c (r)=m / r^3, where is a positive constant of suitable dimensions and r is the distance from the center of the orbit. If the particle moves in the same circular orbit of radius r_0 in the combined gravitational potential due to M and V_ c (r), but with a new time period T_1, then (T_1^2-T_0^2 ) / T_1^2 is given by [ G is the gravitational constant.]