Find the gravitation field at a distance of 20000 km from centre of earth.
(Given `R_("earth") =6400km, M_("earth") = 6xx 10^(24)kg)`:

Options

A. `1.53m//s^(2)`
B. `7.12m//s^(2)`
C. `3.06m//s^(2)`
D. `1.8 m//s^(2)`

Answer

C

Explanation

`g'=(GM)/(R^(3)).r`
`=(GM)/(R^(2)).(r )/(R )=g.(r )/(R )`
`=9.8 xx (2000)/(6400) =9.8 xx (20)/(64)=3.06 m//s^(2)`