The ratio of the weights of a body on the Earth's surface to that on the surface of a planet is `9 : 4`. The mass of the planet is `(1)/(9) th` of that of the Earth, what is the radius of the planet ? (Tale the planets to have the same mass density).

Answer

2

Explanation

`g=(GM)/(R^(2))`
`4/g=(g_(p))/(g_(E))=1/9(R_(E))/(R_(P))impliesR_(p)^(2)=(R^(2))/4` So `R_(p)=R/2`