Question

What will be the acceleration due to gravity whose mass is 8 times the mass of the earth and whoes radius is twice that of earth

Answer 1

$f = \frac{g \times m}{{r }^{2} }$

if mass is octupled and radius doubled

$f = \frac{g \times 8m}{ {2r}^{2} }$

Hence

$f = \frac{g \times m}{ {r}^{2} } \times 4$

This implies that the acceleration due to gravity would be 4 times of the acceleration of gravity on Earth

Hence the acceleration due to gravity would be

$4 \times 9.8 \: ms {}^{ - 2}$

$39.2 \: ms {}^{ - 2}$