parallelogram law

American  

noun

1. Mathematics, Physics. a rule for adding two vectors, as forces parallelogram of forces, by placing the point of application of one at the point of origin of the other and obtaining their sum by constructing the line connecting the two remaining end points, the sum being the diagonal of the parallelogram whose adjacent sides are the two vectors.

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Example Sentences

By contrast, the ancients had known, by our reckoning, only four physical laws: the law of the lever, the optical law of reflection, the law of buoyancy and the parallelogram law of velocities.16 Or, rather, the ancients had known four principles that we call laws.

From Literature

But then these two areas are equal, because they are triangles on the same base AS, and between the same parallels BP, AS; for by the parallelogram law BP is parallel to AD.

From Project Gutenberg