An Etymological Dictionary of Astronomy and Astrophysics
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A → force that is always directed toward a fixed point and whose → magnitude depends only on the distance from that point. Mathematically, F is a central force if and only if: F = f(r)r₁ = f(r)r/r, where r₁ = r/r is a unit → vector in the direction of r. If f(r) < 0 the force is said to be → attractive toward the source. If f(r) > 0 the force is said to be → repulsive from the source. In other words, a central force is one whose → potential, V(r), depends only on the → distance from the source. → Gravitational force and → electrostatic force are central, with V(r)∝ 1/r.

→ central; → force.