The literature of graphical statics and its technical applications is very extensive.
This is subject tc the same relations as a couple in statics; it may be represented by a vector which will, however, in general vary with the position of 0.
The mode of distribution of a force applied to a solid body requires to be considered when its stiffness and strength are treated of; but, in questions respecting the action of a force upon a rigid body considered as a whole, the resultant of the distributed force, determined according to the principles of statics, and considered as acting in a single line and applied at a single point, may, for the occasion, be substituted for the force as really distributed.
Forces applied to Mechanism Classed.If 0 be the obliquity of a force F applied to a piece of a machinethat is, the angle made by the direction of the force with the direction of motion of its point of applicationthen by the principles of statics, F may be resolved into two rectangular components, viz.
Now from the laws of statics it is known that, in order that a system of forces applied to a system of connected points may be in equilibrium, it is necessary that the sum formed by putting together the products of the forces by the respective distances through which their points of application are capable of moving simultaneously, each along the direction of the force applied to it, shall be zero, products being considered positive or negative according as, the direction of the forces and the possible motions of their points of application are the same or opposite.
