A solid sphere of mass m and radius r is placed inside a hollow thin spherical shell of mass M and radius R as shown in figure`-6.30`. A particle of mass m' is placed on the line joining the two centres at a distance x from the point of contact of the sphere and the shell. Find the magnitude of the resultant gravitational force on this - particle due to the sphere and the shell if (a) `r lt x lt 2r, (b) 2rlt x lt 2R "and"(c) xgt2R`.

Answer

`(Gmm'(x-r))/(r^(3))(b)(Gmm')/((x-r)^(2))(c)(GMm')/((x-R)^(2))+(Gmm')/((x-r)^(2))`