[填空题]
Four 1.0-kg masses are located at the corners of a jf-nj6d*ans:-w x*1tzjnz(q1 ,lzqh square 0.50 m on each side. lb75jnl y3- -zq*oftcFind the magnitude and direction of the gravitational force on a l*fc-o7l53q-yb j z tnfifth 1.0-kg mass placed at the midpoint of the bottom side of the square. $\times 10^{-10}$
