[填空题]
Four 9.5-kg spheres ar -rb8t/8ar :27kizkcj8;i0d o hpoxide located at the corners of a sw ibsrwjt.(o0q *;;dmquare of side 0.60 m. Calculate the magnitude and direction of the total gravitatj *tws;w rd0io (qb.m;ional force exerted on one sphere by the other three. $\times 10^{-1} \mathrm{~N} \text { at }$ $^{\circ}$