If in a system the force of attraction between two point masses of 1 kg each situated 1 km apart is taken as a unit force and is called notwen (newton written in reverse order). If G = 6.67$\times {10}^{-11}\mathrm{N}-{\mathrm{m}}^2{\mathrm{kg}}^{-2}$in SI units, the relation of newton and notwen is:

If two point masses each of masses 1 kg are separated a distance 1m they experience a force $6.67\times {10}^{-11}$newtons,

We know, $\mathrm{F}=\mathrm{G}\frac{{\mathrm{m}}_1{\mathrm{m}}_2}{{\mathrm{r}}^2}$

1 notwen = $6.67\times {10}^{-11}\times \frac{{\left(1\mathrm{kg}\right)}^2}{{\left(1\mathrm{km}\right)}^2}$

                    = $6.67\times {10}^{-11}\times {10}^{-6}\frac{{\left(1\mathrm{kg}\right)}^2}{{\left(1\mathrm{m}\right)}^2}$

                  = $6.67\times {10}^{-11}\times {10}^{-6}\mathrm{newtons}$

1 notwen = $6.67\times {10}^{-17}\mathrm{newtons}$