The weight of a body at the surface of earth is \( 18 \, \text{N} \). The weight of the body at an altitude of \( 3200 \, \text{km} \) above the Earth’s surface is (given, radius of earth \( R_e = 6400 \, \text{km} \) ):
\( 9.8 \, \text{N} \)
\( 4.9 \, \text{N} \)
\( 8 \, \text{N} \)
\( 19.6 \, \text{N} \)