A point charge of +Q is placed at the center of a square, and a second
,bnfa qp(aj1xa *v+f) point charge of -Q is placed at the upper-left corner. It is observed that an electrostatic force of
+,va(*x abf fp1nja)q 2.0 N acts on the positive charge at the center. What is the magnitude of the force that acts on the center charge if a third charge of -Q is placed at the lower-left corner?