A body weighs W newton at the surface of the earth. Its weight at a height equal to half the radius of the earth, will be

Options

A. `(W)/(2)`
B. `(2W)/(3)`
C. `(4W)/(9)`
D. `(8W)/(15)`

Answer

C

Explanation

`g'=g(R^(2))/((R+(R )/(2))^(2))=(4)/(9)g`
`therefore W' = mg'=(4)/(9)mg = (4)/(9) W`