CONCEPTS

# What is the energy?

We explain to you what energy is in physics, what is potential and kinetic energy? In addition, how the force acts and what is the work.

1. ### What is the energy?

In physics, we refer to energy as the ability of a system or a phenomenon to carry out a given job . The word energy comes from the Greek  energetic  that translates “force of action” or “work force.” It is a concept widely used in this science and in others in general, with different meanings and meanings.

This ability to perform work is key in the interest of physics in energy, since this discipline studies the systems of nature as actions and reactions in which matter is interrelated and energy is transferred from one system to another, from One way to another.

In fact, energy  is governed, according to the Second Law of Thermodynamics (in classical mechanics, that is, Newtonian), which states that the amount of energy in the universe is always stable, permanent, and cannot and cannot be created. nor be destroyed, only be transformed.

On the other hand, in relativistic mechanics, governed by Albert Einstein’s Theory of Relativity , energy and matter ( mass ) have a closer relationship that defines the famous equation E = m.c2, that is, energy is the same a Mass by the speed of light squared. Thus, all bodies, simply because they are composed of matter, would possess an additional dose of energy that must be taken into account.

On the other hand,  energy (E) and work (W) are equivalent , so they are measured in the same type of units: Joules or Joules (J), that is, Newtons per meter (N / m).

1. ### Potential energy

This type of energy is associated with a specific body or physical system, by virtue of its position or its height, that is, based on a field of forces of which it is a part. This type of energy can be classified into:

• Gravitational potential energy . The one that takes into account the field of forces around the planet’s gravity , that is, that attributes to a body an amount of energy based on the possible fall. For example, a ball located on the ledge of a building has enormous potential energy that, upon falling, would become kinetic energy ( movement ).
• Potential electrostatic energy . It occurs when the body or system is in relation to a certain electric field, such as an electrical circuit or an electromagnet.
• Elastic potential energy . That which has to do with the field of tensions and internal forces of a deformable body, when it has shape memory. This means that certain bodies or systems can undergo a force and force them to deform, but by releasing them they will recover their original position and shape, releasing an amount of potential energy that was accumulated inside them during the time it was deformed. This is how springs work, for example.
1. ### Kinetic energy A body that travels at a certain speed will have associated kinetic energy.

Kinetic energy is the energy of movement, and is usually designated with the signs  K ,  T  or  c , since it is extremely important for the various fields of physics. Thus, a body that travels at a certain speed will have an associated kinetic energy , which can feel like a blow when stopped abruptly or get in its way.

The kinetic energy of the objects or particles of a system can be added to calculate its internal energy. In fact, heat is nothing other than the result of the kinetic energy of the particles of a substance stirring faster.

The traditional formula for calculating the kinetic energy of a body that moves at a given speed (v) is as follows: Ec = ½.m.v2

1. ### Strength

In physics, force is a vector magnitude (endowed with direction, direction), which is capable of modifying the amount of movement or the shape of a particular body or material . It is not equivalent to effort or energy.

The force is measured in the International System by Newtons (N), defined as the amount of force needed to accelerate an object of 1kg of mass in 1m / s2.

1. ### Job

In Newtonian (classical) physics, work is defined as the result of a force that alters the movement or position of a body .

Such work will be equivalent to the amount of energy required to move it rapidly. In that sense, there can be no increase in work, as it is nothing more than a transit of energy.

The work is represented by the symbol  W  ( Work English  ) and is a scalar quantity (without direction) and is expressed in the same units as the energy (joules).