Basic Topics in the Mechanics Course

In this article, we will define the meaning and importance of mechanics, the fields of application of mechanics, the branches of mechanics, and concepts such as statics, dynamics, kinematics, aerodynamics, and hydrostatics. Our topics are as follows:

Mechanics

Mechanics: A branch of science that studies, both graphically and analytically, the force systems acting on bodies and the motions these systems produce in the body.

The Importance of Mechanics

The task of the theoretical natural sciences is to tie the state of the bodies around us and the changes they undergo to clear, definite rules, organize them, and report their results in measured, numerical terms. The essential condition required to accomplish this is provided by our observations, which have continued for centuries.

A human being is a creature that can think about the causes of events, develop them, and use them for its own benefit. Since its existence, it has studied the events unfolding around it and nature itself. The technical level we have reached today is the sum of observations that began with the very first humans.
Lifting and throwing a stone, or stacking stones to form a structure, people walking or running, water flowing, the wind blowing, and similar things are each physical events — among the first things people saw or were able to do.

As a result of studying and evaluating such events, various systems were developed. Many ancient civilizations successfully used “levers,” developed for lifting heavy loads. Making use of the energy carried by moving bodies, and studying how bodies interact with one another, drew people in and made it necessary for them to learn about these things.
The knowledge gained through this study tied these events and their causes to definite rules.

Fields of Application of Mechanics

Today, just as in the past, knowledge of mechanics holds a large place in human life. Opening a door, tightening a screw, the flow of water, the flight of an aircraft, a car’s ability to move, every kind of human movement, the operation of machines, and many more things one could list all follow the principles of mechanics.

From a lever, to a clock used for measuring time, to the most advanced spacecraft, knowledge of mechanics is needed everywhere. In particular, a significant part of the lives of those receiving a technical education will involve working with mechanical systems. This is why the subject of mechanics carries such importance.

Among the scientists who dealt with mechanical problems and whose principles form the basis of today’s industrial developments, the ones most relevant to our subject are: Aristotle, Archimedes, Newton, Pascal, Galileo, Hooke, and Euler.

Branches of mechanics

Mechanics of Liquids (Hydrostatics)

Hydrostatics studies the equilibrium conditions of liquids at rest. Liquids exert a pressure on the base of the container they are in. Liquids are also substances with a flowing property, taking the shape of the container they are held in.

According to Pascal’s principle, liquids transmit any pressure applied to them equally to the surfaces they touch. As a result, a small force acting over a small area produces a large force over a large area. In machining, the system built to make use of the energy carried by pressurized liquids to produce various motions is called a hydraulic system.

Liquids are fluid substances and transmit pressure as it is applied to them. For this reason, a liquid transmits force in direct proportion to the surface area it acts on. As shown in the figure, the pressure provided by the small piston is transmitted by the liquid to the large piston and turns into a large force. Because of this property, liquids are used to generate pressure and force in presses, lifting machines, pumps, hydraulic power units, etc.

Pascal's law — With the application of Pascal’s principle, it became possible to lift large loads with small forces.

Mechanics of Gases (Aerodynamics)

Aerodynamics: Studies the motion of all fluids in the form of air or gas. For example, the shapes given to aircraft wings to increase flight efficiency are calculated using this branch — such as making the wings and certain sections oval in form. Gases are flowing, volatile substances that can change in volume and pressure under the effect of heat.

Mechanics of Solids

A solid body: any body that, under the effect of forces, preserves its geometric shape and dimensions exactly in every case — that is, undergoes no change in shape — is called a “solid body.”
However, no body shows this property perfectly. Every body changes shape somewhat under the effect of force. But depending on the magnitude of the force and the dimensions of the body, if the amount of shape change is so small it can be neglected, such bodies can be considered solid bodies.

For example, the atoms of steel are bonded to one another very strongly. As a result, steel does not easily change shape. Because of this property, we find steel used in the material of many machine components.
The mechanics of solids is divided into three main branches according to the effects of factors such as equilibrium, force, velocity, and acceleration