Two particles, each with charge Q, and a third particle, with a charge q, are placed at the vertices of an equilateral triangle as shown. The total force on the particle with charge q is:

Question

Quizplus · Accepted Answer

Since the three particles are located at the vertices of an equilateral triangle, the angle between any two particles is 60 degrees. When calculating the net force on the particle with charge q, the forces from the two particles with charge Q will be at an angle of 60 degrees to each other. These two forces can be resolved into a perpendicular component (to the bottom side of the triangle) and a parallel component (to the bottom side of the triangle). The perpendicular components will cancel out each other due to symmetry, and the parallel components will add up to create a net force that is perpendicular to the bottom side of the triangle. Therefore, the correct answer is D) perpendicular to the bottom side of the triangle.

Two Particles, Each with Charge Q, and a Third Particle