The article below will focus on internal energy and how to change it. Here we will familiarize ourselves with the general definition of renewable energy, with its meaning and two types of state changes by the energy that a physical body, an object possesses. In particular, the phenomenon of heat transfer and the completion of work will be considered.
Introduction
Internal energy is that part of the resource of a system of thermodynamic nature, which is not dependent on a specific reference system. It can change its meaning within the studied problem.
Characteristics of equal value in the reference frame, in relation to which the central mass of the body / object of macroscopic dimensions is a state of rest, have the same total and internal energies. They always match each other. The set of parts that make up the total energy entering the internal is unstable and depends on the conditions of the problem being solved. In other words, renewable energy is not a specific type of energy resource. It is a common set of a number of components of the full energy system, which vary with specific situations. The methods for changing internal energy are based on two basic principles: heat transfer and work performance.
RE is a specific concept for systems of thermodynamic nature. It allows one to introduce various quantities into the use of physics, such as temperature and entropy, the dimension of the chemical potential, and the mass of the substances that make up the system.
Completing of the work
There are two ways to change the internal energy of bodies (a). The first is formed through the process of doing direct work on an object. The second is the heat transfer phenomenon.
In cases where the work is performed by the body itself, its internal energy index will decrease. When the process is completed by someone or something above the body, then its VE indicator will increase. In this case, a transformation of the mechanical energy resource into the internal type of energy that the object possesses is observed. Everything can also flow and vice versa: mechanical into the inside.
Heat transfer increases the value of RE. However, if the body cools down, then the energy will decrease. With the constant maintenance of heat translation, the indicator will increase. The compression of gases is an example of an increase in the RE index, and their expansion (of gases) is a consequence of a decrease in the value of internal energy.
Heat transfer phenomenon
The change in internal energy by heat transfer is an increase / decrease in energy potential. The body possesses it, without carrying out certain (in particular mechanical) work. The transferred amount of energy is called heat (Q, J), and the process itself is subordinate to the general EWS. Making changes in renewable energy is always reflected by an increase or decrease in body temperature.
Both methods of changing internal energy (work and heat transfer) can be performed in relation to one object in the same order, that is, they can be combined.
You can change the RE, for example, by creating friction. Here, the completion of mechanical work (friction) and the heat transfer phenomenon are clearly monitored. Similarly, our ancestors tried to make fire. They created friction between the wood, the ignition temperature of which corresponds to the mark of 250 ° C.
The change in the internal energy of the body through work or heat transfer can occur at the same time interval, that is, these two types of tools can work together. However, simple friction in a particular case will not be enough. To do this, one branch had to be pointed. Currently, a person can get fire by friction of matches, the heads of which are covered with a combustible substance, flammable at 60-100 ° C. The first such products began to be created in the 30s of the XIX century. These were phosphoric matches. They are able to catch fire at a relatively low temperature - 60 ° C. Currently, they use Swedish matches, which were put into production in 1855.
Energy dependence
Speaking about ways to change internal energy, it will be important to mention also the dependence of this indicator on temperature. The fact is that the amount of this energy resource is due to the average value of the kinetic energy concentrated in the molecule of the body, which, in turn, directly depends on the temperature indicator. It is for this reason that a change in temperature always leads to a change in RE. It also follows from this that heating leads to an increase in energy, and cooling causes its decrease.
Temperature and heat transfer
Ways to change the internal energy of the body are divided into: heat transfer and the completion of mechanical work. However, it will be important to know that the amount of heat and temperature are not the same thing. These concepts should not be confused. Temperature values are determined in degrees, and the amount of heat transferred or transferred is determined using joules (J).
The contact of two bodies, one of which will be hotter, always leads to the loss of heat by one (hotter) and to its acquisition by the other (colder).
It is important to note that both methods of changing the body's renewable energy always lead to the same results. It is impossible to determine in what way its change was achieved by the final state of the body.