Final answer:
The question pertains to finding the position at which a third charge experiences no net electrical force in a system, a concept in high school Physics.
Step-by-step explanation:
The subject of this question is Physics, particularly dealing with electric forces and fields in electrostatics. The question concerns finding the position p3 where a point charge q3 experiences no force. To solve for p3, one would need to apply Coulomb's Law and concept on electric fields. Considering two charges placed on the x-axis, to make the electric field vanish at a certain point due to these charges, the magnitude of the electric fields due to each charge must be equal and opposite in direction. By strategically placing q3 at a point where these conditions are met, the net force on q3 due to the other charges will be zero.
For instance, if we have two charges with equal magnitude but opposite sign located symmetrically on the x-axis, the point where the electric field vanishes would be at the origin. Moving any charge q3 across the axis can change where this zero electric field point is situated. In more complex configurations, the superposition principle is used to determine the resultant electric field, and hence the force on a charge q3.