In physics, a classical force is a name given to a net influence that causes a free body with mass to accelerate. A net (or resultant) force which causes such acceleration may be the non-zero additive sum of many different forces acting on a body.

Force is a vector quantity defined as the rate of change of momentum induced in a free body by the net force acting on it, and therefore force has a direction associated with it. The SI unit of force is the newton.

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