Question

Suppose a planet exist whose mass and diameter both are twice of earth. Calculate acceleration due to gravity on this planet. On earth, take `g=9.8 m//s`.

Answer 1

Here, `M_(p)=2M_(e),D_(p)=2D_(e)` or `R_(p)=2R_(e)`
`g_(p)=?g_(e)=9.8m//s^(2)`.
As `g_(p)(GM_(p))/(R_(p)^(2))` and `g_(p)=(GM_(e))/(R_(e)^(2))`
`:. (g_(p))/(g_(e))=(M_(p))/(R_(p)^(2))xx(R_(e)^(2))/M_(e)=((1)/(2))^(2)=(1)/(2)`
`g_(p)=(1)/(2)g_(e)=(1)/(2)xx9.8=4.9m//s^(2)`