The centres of a ring of mass `m` and a sphere of mass `M` of equal radius `R`, are at a distance `sqrt(8) R` apart as shown. The force of attraction between the ring and the sphere is

Options

A. `(2sqrt(2))/27(GmM)/(R^(2))`
B. `(GmM)/(8R^(2))`
C. `(GmM)/(9R^(2))`
D. `(sqrt(2))/9(GmM)/(9R^(2))`

Answer

A

Explanation

`dF=(GMdm)/(3R^(2)), F=SigmadFcos theta`(or) for a ring, `F=(GMmx)/((R^(2)+x^(2))^(3//2)), x=sqrt(8)R`