Newton's law of gravity is given by:
[tex]F=G\frac{m_1m_2}{r^2}[/tex]where G is the gravitational constant, m1 and m2 are the masses and r is the distance between them.
To calculate the weight using this law we need to remember that:
[tex]\begin{gathered} G=6.67\times10^{-11}\frac{m^3}{kg\cdot s^2} \\ \text{Mass of the eart:} \\ M=5.972\times10^{24}\operatorname{kg} \\ \text{Radius of earth:} \\ r=6.3781\times10^6m \end{gathered}[/tex]Plugging this values and your mass in Newton's law we have:
[tex]\begin{gathered} F=6.67\times10^{-11}\frac{m^3}{kg\cdot s^2}\cdot\frac{(52kg\text{)(}5.972\times10^{24}\operatorname{kg})}{(6.3781\times10^6m)^2} \\ F=509.17N \end{gathered}[/tex]Therefore your weight is 509.17 N