The mass of the moon is `1/81` of the earth but the gravitational pull is `1/6` of the earth. It is due to the fact that

Options

A. the radius of earth is `(9)/(sqrt(6))` of the moon
B. the radius of moon is `(81)/(6)` of the moon
C. moon is the satellite of the earth
D. None of the above

Answer

A

Explanation

Gravitational pull depends upon the acceleration due to gravity on that planet
`M_(,)=(1)/(81)M_(e),g_(m)=(1)/(6)g_(e)`
By the relation, `g=(GM)/(R^(2))`
`(R_(e))/(R_(m))=((M_(e))/(M_(m))xx(g_(m))/(g_(e)))^(1//2)(81xx(1)/(6))^(1//2):. R_(e)=(9)/(sqrt(6))R_(m)`.