A body weighs 63N on the surface of the earth then its weight at a height equal to half of the radius of earth is

We have the weight of a body on the surface

$W=mg=63$N

$W_h$  is the weight at $h=\frac{R}{2}$

$W_h=m{g}_h \left(\begin{array}{c}\because g_h=\frac{GM}{{(R+h)}^2}\\ g_h=\frac{GM}{{(R+\frac{R}{2})}^2}=\frac{4}{9}\frac{GM}{R^2}\\ g_h=\frac{4}{9}g\end{array}\right)$

$W_h=m\times \frac{4}{9}g$

$W_h=\frac{4}{9}\times mg$

$W_h=\frac{4}{9}\times 63=28\text{N}$