Three identical particle A, B and C of mass 100kg each are placed...

Given here, $m = 100kg$

Gravitational force, ${F}_{AP} = \dfrac{G{m}^{2}}{{\left(13\sqrt{2}\right)}^{2}}$,

${F}_{BP} = \dfrac{G{m}^{2}}{{\left(13\right)}^{2}}$ and ${F}_{CP} = \dfrac{G{m}^{2}}{{\left(13\sqrt{2}\right)}^{2}}$

Net gravitational force,

{F}_{net} = {F}_{BP} + {F}_{AP}\cos 45 ° + {F}_{CP}\cos 45 °

$= \dfrac{G × {10}^{4}}{{13}^{2}}\left(1 + \dfrac{1}{\sqrt{2}}\right)$

$F ≃ 100G$