# Problem: 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.

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###### Problem Details

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.

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Coulomb's Law (Electric Force) concept. You can view video lessons to learn Coulomb's Law (Electric Force) Or if you need more Coulomb's Law (Electric Force) practice, you can also practice Coulomb's Law (Electric Force) practice problems .

What is the difficulty of this problem?

Our tutors rated the difficulty of An equilateral triangle  ABC. A positive point charge +q is ... as medium difficulty.

How long does this problem take to solve?

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What professor is this problem relevant for?

Based on our data, we think this problem is relevant for Professor Schulte's class at UCF.