Force is a physical quantity that describes the interaction between two objects. It is a vector quantity, meaning it has both magnitude and direction.
Charge is a fundamental property of matter that determines how it interacts with electric and magnetic fields. It can be either positive or negative.
The arrow above the F represents the direction of the force. In this case, it indicates the direction in which the force is acting on the 1 nC charge at the bottom.
The unit of force is Newton (N). It is named after Sir Isaac Newton and is defined as the amount of force required to accelerate a mass of 1 kilogram at a rate of 1 meter per second squared.
The magnitude of the force can be calculated using Coulomb's Law, which states that the force between two charges is directly proportional to the product of their magnitudes and inversely proportional to the square of the distance between them. It can be expressed as F = (k * q1 * q2) / r^2, where k is the Coulomb's constant, q1 and q2 are the charges, and r is the distance between them.