Answer:
a) 1/4 what it is now
Explanation:
As we know that force of gravitation between two planets at some distance "r" from each other is given as
[tex]F_g = \frac{Gm_1m_2}{r^2}[/tex]
now since we know that if the distance between Earth and Sun is changed
So the force of gravity will be given as
[tex]\frac{F_g'}{F_g} = \frac{r_1^2}{r_2^2}[/tex]
now we know that the distance between sun and earth is changed to twice the initial distance between them
so we have
[tex]r_2 = 2r_1[/tex]
so new gravitational force between sun and earth is given as
[tex]F_g' = \frac{r_1^2}{(2r_1)^2}F_g[/tex]
[tex]F_g' = \frac{1}{4}F_g[/tex]