Agency that alters the direction, speed, or shape that a body would exhibit in the absence of any external influence. It is a vector quantity, having both magnitude and direction. Force is commonly explained in terms of Newton's laws of motion. All known natural forces can be traced to the fundamental interactions. Force is measured in newtons (N); a force of 1 N will accelerate a mass of 1 kg at a rate of 1 m/sec/sec. See also centrifugal force; Coriolis force; electromagnetic force; Coulomb force; magnetic force; strong force; weak force.

This entry comes from Encyclopædia Britannica Concise.
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