Question

PLEASE HELP ME~

If Earth's mass and radius both suddenly doubled, what would be the new value of the acceleration of gravity near Earth's surface?
(a) 9.80 m/s2
(b) 4.90 m/s2
(c) 2.45 m/s2
(d) 19.6 m/s2
(e) 12.6 m/s2

Answer 1

\[a=\frac{ Gm }{ r^2 }\]Double mass and radius to get\[a' = \frac{ G(2m) }{ \left( 2r \right)^2 } = \frac{2Gm}{4r^2}=\frac{Gm}{2r^2}\]Compare the two.

Answer 2

@ospreytriple what do you think the answer? Cos I don't know too haha

Answer 3

I won't tell you the answer, but compare the two equations above. what is the relationship between a and a' ?

Answer 4

@ospreytriple I don't know :3