Statics is the action of one body on another. A force is either a push or a pull. A force tends to move a body in the direction of its action. The action of a force is characterized by its magnitude, by the direction of its action, and by its point of application. Thus, force is a vector quantity, because its effect depends on the direction as well as on the magnitude of the action. Forces are classified as either contact or body forces. A contact force is produced by direct physical contact; an example is the force exerted on a
Physical quantity Physical quantity A physical quantity is a physical property of a phenomenon, body, or substance, that can be quantified by measurement. A physical quantity can be expressed as the combination of a magnitude expressed by a number – usually a real number – and a unit: formula_1 where formula_2 is the magnitude and formula_3 is the unit. For example, (the mass of the neutron), or (the speed of light). The same physical quantity formula_4 can be represented equivalently in many unit systems, "i.e." formula_5. Symbols for quantities should be chosen according to the international recommendations of ISO/IEC 80000, the IUPAP