The Science of Mechanics

Mechanics deals with a variety of problems, but notwithstanding this variety they fall under one of the following classifications:

1 .Determining the trajectory described by the points of a moving body, the position of any one of the points in its trajectory, its speed and acceleration, etc., in short, the solution of any of its individual points of the trajectory, its speed and acceleration, etc., in short, the solution of any of its individual points independent of the force applied.

This branch of mechanics is called kinematics. Kinematics deals with the relationship between the geometric elements of motion and time, irrespective of the forces acting on the body in motion.

2.Determining the nature of motion of a body as related to the forces acting on the body, or, conversely, determining the forces causing the motion. This type of problem is dealt with in the branch of mechanics called kinetics.

Mechanics also treats of terrestrial bodies in a state of rest, that is, a state of equilibrium. Here we seek the conditions under which forces acting on a body are brought into equilibrium, for knowing these conditions, engineers can ensure rigidity and strength to the structures they are building.

That part of kinetics dealing with equilibrium of forces and the consequent state of rest of a body is known as statics, while the investigation of motion of bodies under the action of forces applied to them constitutes another branch of kinetics called dynamics.

Such are the sciences embraced by mechanics, and their fundamentals are tought in the following order: statics, kinematics, and dynamics.

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Fundamental Element of Mechanics

The motion of a body occurs in space, therefore space is one of the fundamental elements in mechanics. Time is likewise such an element in mechanics.

Every point of a moving body describes a path of definite form relative to a basic system, this path is called a trajectory. A trajectory may be either of straight or curved lines, in accordance with which the motion of a point is then described either as rectilinear or curvilinear, A moving point traverses a definite distance, the length of which as covered in a definite interval of time will depend upon the speed of the moving point. If the point travels equal distances in equal intervals of time, its speed will be constant and its motion is then said to be uniform. In other cases the motion is said to be non-uniform, or variable

If speed changes at an equal rate in equal intervals of time, the motion is said to be either uniformly accelerated or uniformly retarded, a change in speed is called acceleration.

In investigating mechanical motion of bodies and their state of rest (as a particular case of motion, another quantity is met with which determines the action of one body upon another; that quantity is called force.

All these elements will be dealt with in detail along with others pertaining to mechanics, as we proceed.

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