3 charges are at the corners of an equilateral triangle with sides 1 m in length. The bottom two charges are each negative 4 Coulombs. The top charge is positive 3 Coulombs. There are vectors from the top charge north labeled A, south labeled C, east labeled B, and west labeled D.

Question

Which vector best represents the net force acting on the +3C charge in the diagram?

A
B
C
D

Answer 1

To determine which vector best represents the net force acting on the +3 Coulomb charge at the top of the equilateral triangle, we need to consider the forces exerted on it by the two negative charges located at the bottom corners of the triangle.

1. Force due to the Left Charge (Bottom Left):

   • The charge is negative (-4 C), and the +3 C charge will be repelled by it. The direction of the force will be towards the negative charge. The force vector points downwards and slightly to the left.

2. Force due to the Right Charge (Bottom Right):

   • Similarly, the charge at the bottom right (also -4 C) will repel the +3 C charge, also pointing downwards and slightly to the right.

Both forces will have components that are directed downwards, with some leftward and rightward components, respectively.

3. Net Force Calculation:
   • The vertical (downward) components of the forces from both bottom charges will combine linearly since both forces are directed downwards.
   • The horizontal (left and right) components will cancel each other out since the charges are symmetrically placed with respect to the +3 C charge.

Therefore, the net force acting on the +3 C charge will be directed straight downwards, which corresponds to vector C labeled "South."

Thus, the correct answer is C.