Final answer:
To balance the electric forces on q1, the third charge q3 must be placed on the side opposite to q2, at a distance where the attractive force between q1 and q3 equals the attractive force between q1 and q2. The specific point can be found using Coulomb's law and the given charge values and distances.
Step-by-step explanation:
To determine where to place a third charge q3 so that the net electric force on q1 is zero, we need to understand Coulomb's law, which states that the electric force between two point charges is proportional to the product of their charges and inversely proportional to the square of the distance between them. For q1 to experience no net force, the force exerted by q3 must be equal in magnitude and opposite in direction to the force exerted by q2 on q1.
Since q1 and q2 have opposite signs, they attract each other. Therefore, q3 must be placed on the opposite side of q1 to q2, to exert a force of attraction on q1 that balances the attraction from q2. To find the distance x from q1 to where q3 should be placed, we can set up the equation based on Coulomb's law:
F(q1,q2) = F(q1,q3)
To solve for x, we need to know the distances and magnitudes of the charges involved, which are provided in the question. Bear in mind that the point will lie at a location where the forces due to q2 and q3 on q1 are balanced, that is, along the line joining q1 and q2 but farther from q1 than q2.