Four charges, qa, qb, qc, qd are fixed at the corners of a square. A charge q that is free to move located at the exact center of the square. Classify the scenarios described according to the force that would be exerted on the center q. Assume in each case that q is a positive charge. Do not assume that the fixed charges have equal magnitudes unless the scenario defines such an equality.

Four charges, qa, qb, qc, qd are fixed at the corners of a square. A charge q that is free to move located at the exact center of the square. Classify the scenarios described according to the force that would be exerted on the center q. Assume in each case that q is a positive charge. Do not assume that the fixed charges have equal magnitudes unless the scenario defines such an equality.