Final answer:
The total electric force exerted on a charge Q by charges q1 and q2 can be calculated using Coulomb's law, summing the individual forces from each charge and combining them vectorially.
Step-by-step explanation:
The magnitude of the total electric force that charges q1 and q2 exert on charge Q can be found using Coulomb's law, which states that the electrostatic force (F) between two point charges is proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance (r) between them.
The formula is given by F = k|qQ|/r², where k is Coulomb's constant (8.99 x 10⁹ Nm²/C²). For charge Q, we would sum the forces exerted by each charge q1 and q2 separately and then combine them vectorially to find the total force.
For example, if we consider the force on the middle charge q2 due to charge q1 from your information, we would apply F = k|q1q2|/r², and similarly for the force due to q3 on q2.
The electric field strength due to a charge q1 at a point in space is E = k|q1|/r² and the force exerted on a charge Q in this electric field is F = Q * E, where E is the electric field due to another charge like q1.