An equilateral triangle ABC. A positive point charge +q is located at each of the three vertices A, B, and C. Each side of the triangle is of length a. A point charge Q (that may be positive or negative) is placed at the mid-point between B and C. Is it possible to choose the value of Q (that is non-zero) such that the force on Q is zero?
A) Yes, because the forces on Q are vectors and three vectors can add to zero.
B) No, because the forces on Q are vectors and three vectors can never add to zero.
C) Yes, because the electric force at the mid-point between B and C is zero whether a charge is placed there or not.
D) No, because the forces on Q due to the charges at B and C point in the same direction.
E) No, because a fourth charge would be needed to cancel the force on Q due to the charge at A.