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

<p>The weight of an object at a height h from the Earth&#39;s surface is given by:</p> <p>$W&#39; = W \left(\frac{R}{{R + h}}\right)^2$</p> <p>where:</p> <ul> <li>W&#39; is the weight at height h,</li> <li>W is the weight at the Earth&#39;s surface,</li> <li>R is the radius of the Earth,</li> <li>h is the height above the Earth&#39;s surface.</li> </ul> <p>In this problem, the weight at the Earth&#39;s surface W is given as 18 N, the radius of the Earth R is given as 6400 km, and the height h is given as 3200 km. Substituting these values into the equation gives:</p> <p>$$W&#39; = 18 N \left(\frac{6400~km}{{6400~km + 3200~km}}\right)^2 = 18 N \left(\frac{2}{3}\right)^2 = 18 N \cdot \frac{4}{9} = 8 N$$</p> <p>Therefore, the weight of the body at an altitude of 3200 km above the Earth&#39;s surface is 8 N.</p>