MET 201 Statics - Chapter 2

Force

A force represents the action of one body on another. It is generally characterized by its point of application, its magnitude, and its direction. Force acting on a given particle, however, have the same point of application.

Magnitude of a force

characterized by a certain number of units

Line of action

The infinite straight line along which the force acts; it is characterized by the angle it forms with some fixed axis.

Resultant of the force P and Q

two forces P and Q acting on a particle A can be replaced by a single force R that has the same effect on the particle.

Parallelogram law

The method for finding the resultant. We can obtain R, by constructing a parallelogram, using P and Q as two adjacent sides. The diagonal that passes through A represents the resultant.

Scalars

Physical quantities that have magnitude but not direction, such as volume, mass, or energy, are represented by plain numbers.

Vectors

Mathematical expressions possessing magnitude and direction, which add according to the parallelogram law.