Question

The weight of a body at the surface of earth is $18N$. The weight of the body at an altitude of $3200km$ above the earth's surface is (given, radius of earth $R_e=6400km$ ):

• A. 19.6 N
• B. 9.8 N
• C. 4.9 N
• D. 8 N

Answer 1

Answer: (D)

Acceleration due to gravity at height $h$
$g^{\prime }=\frac{g}{{\left[1+\frac{h}{R}\right]}^2}$
So weight at given height
$m{g}^{\prime }=\frac{mg}{{\left[1+\frac{h}{R}\right]}^2}=\frac{18}{{\left[1+\frac{1}{2}\right]}^2}=8N$