A point charge of +Q is placed at the center of a square, and a second point c
f 21kxkxv)m h ta.b70 m(dku6fharge of -Q is placed at the upp
hftma 60)vf2m(x.kk k b7xud1er-left corner. It is observed that an electrostatic force of 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?