Question

The decrease in trhe value of g on going to a height above the earth's surface will be :-

• A. $g/2$
• B. $\frac{5g}{9}$
• C. $\frac{4g}{9}$
• D. $\frac{g}{3}$

Answer 1

The correct option is B $\frac{5g}{9}$

$g=\frac{GM}{R^2}$

$g$ at height $h$

$g_h=\frac{GM}{{(R+h)}^2}(h=R/2)$

$g_h=\frac{GM}{{(R+\frac{R}{2})}^2}=\frac{4GM}{9R^2}=\frac{4g}{9}$

Decrease value of $g$

$g-\frac{4g}{9}=\frac{5g}{9}$