Question

If $g$ is the acceleration due to gravity on the surface of earth, its value at a height equal to double the radius of earth is

• A. $g$
• B. $\frac{g}{2}$
• C. $\frac{g}{3}$
• D. $\frac{g}{9}$

Answer 1

Answer: (D)

$\frac{g}{9}$

Answer 2

Acceleration due to gravity at a height $h$ from the surface of the earth
$g'=g \frac{1}{\left(1+\frac{h}{R}\right)^{2}}$
Given $h=2 R$
$\therefore g'=g \frac{1}{(1+2)^{2}}$
or $g'=\frac{g}{9}$