kraftfelt

Kraftfält, or force field, is a vector field that assigns to every point in space a force per unit mass in the case of gravity, and a force per unit charge in the case of electricity. More generally, it describes how a system of particles would experience forces due to a surrounding field, enabling the prediction of motion via Newton’s laws.

Common examples are the gravitational field g produced by masses and the electric field E produced by electric charges. The force on a particle with mass m in a gravitational field is F = m g, and the force on a particle with charge q in an electric field is F = q E. The electric and gravitational fields can often be described as gradients of a scalar potential: E = -∇Φ and g = -∇Φ_g. Magnetic fields, described by B, exert forces F = q v × B and are governed by Maxwell’s equations.

Fields obey the superposition principle: the total field is the vector sum of the individual fields. Field strength has direction (the force a positive test particle would experience) and magnitude, measured in units such as N/C for electric fields and N/kg for gravitational fields. Field lines and equipotential surfaces provide intuitive visualizations of the field structure.

Kraftfält are central in physics, engineering, and technology. They model interactions from electric circuits and capacitors to orbital dynamics and sensor technologies. In many practical settings, gravitational fields near Earth’s surface are well approximated as uniform, while electric fields are manipulated in devices like capacitors and detectors. Understanding kraftfält enables analyses of forces, potential energies, and motion across a wide range of physical contexts.