The Collaborative International Dictionary
Parallelogram \Par`al*lel"o*gram\, n. [Gr. ?; ? parallel + ? to write: cf. F. parall['e]logramme. See Parallel, and -gram.] (Geom.) A right-lined quadrilateral figure, whose opposite sides are parallel, and consequently equal; -- sometimes restricted in popular usage to a rectangle, or quadrilateral figure which is longer than it is broad, and with right angles.
Parallelogram of velocities, parallelogram of forces, parallelogram of accelerations, parallelogram of momenta, etc. (Mech.), a parallelogram the diagonal of which represents the resultant of two velocities, forces, accelerations, momenta, etc., both in quantity and direction, when the velocities, forces, accelerations, momenta, etc., are represented in quantity and direction by the two adjacent sides of the parallelogram.
Wiktionary
n. (context mechanics English) A parallelogram, two adjacent sides of which are vectors having the same initial point and representing two forces acting simultaneously upon this point, such that the resultant of the forces is given by the diagonal of the parallelogram that passes through this point.
Usage examples of "parallelogram of forces".
Her mind drew the parallelogram of forces for each ship in the fleet, varying with their depth of keel and their ability to point to windward, correlated it with their positions relative to the coast to the southeast and what she knew of the set of the oceans around here.
If many simultaneously and variously directed forces act on a given body, the direction of its motion cannot coincide with any one of those forces, but will always be a mean- what in mechanics is represented by the diagonal of a parallelogram of forces.
At that moment of four in the afternoon of June 23, the Pendulum was slowing at one end of its swing, then falling back lazily toward the center, regaining speed along the way, slashing confidently through the hidden parallelogram of forces that were its destiny.