The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:
Living creatures seek energy to sustain life, where human civilization needs the energy to work obtained from sources such as fossil oil, nuclear power or solar energy. Also, the planet’s atmosphere and ecological cycles are powered by Earth’s radiant and geothermal energy.
Energy is the quantitative property of physics that must be applied to an object to operate on it or heat it. Energy is a conserved quantity. The law of conservation of energy states that energy can neither be created nor destroyed but can only be converted from one form to another. The SI unit of energy is Joule.
One of the fundamental principles of physics is the law of energy conservation. In a chemical reaction, it controls the microscopic motion of individual atoms. According to the law, “In a closed system, i.e., a system that is isolated from its surroundings, the total energy of the system is conserved.” The law states that, even if energy transformation occurs, the whole energy is conserved in a system. Energy cannot be generated or lost; it can only get transformed from one form to another.
While several forms of energy exist, they are generally classified into kinetic energy and potential energy.
The S.I. unit of kinetic energy is Joule, whereas the English engineering unit is foot-pound.
The concept of work is somewhat smaller than the usual definition of the word. Work on an object is achieved as the force applied pushes it across a path. An individual holding a heavyweight does not work because the force does not move the item from a distance.
In our daily language, the work done is attributed to muscle effort in doing a particular task, while this is not the case with physics. According to the physical definition, work is carried out as the heavyweight is moved from a stationary position.
The SI unit of work is known as Joule (J), named after the English physicist James Prescott Joule from the 19th century, which is now described as the work needed to generate a displacement of one metre by exerting a force of one Newton.
Like energy, we hear a lot about the word power. There are some differences between energy and power. It has a broad multitude of interpretations in daily life. But it has a unique significance in physics, where the rate at which work is done is defined as power.
Power often depends on work; even if a person works at various rates, his power varies at specific intervals. Here the principle of average power is taken into consideration.
The average power can be defined as the total consumption of energy divided by the entire time. In simple words, we can conclude that average power is the average work per unit of time. The rate at which work is performed on an item is known as power, and it is a quantity dependent on time. That’s how quickly a job is done. The powder formula is expressed as:
Power = Work done/ Time taken to complete the work or P = W/t
The S.I unit of power is joule/ second.
Energy transfer refers to energy flow from one spot to another. In contrast, energy transformation in common daily life situations involves energy change from one type to another, for example, from kinetic energy to energy or from potential energy to kinetic energy. Some examples of energy transformation are:
For life and other living things, energy is crucially important. The sun is the origin of all the life on Earth, either directly or indirectly. It is vital to choose our energy sources carefully to influence our natural systems on Earth in ways we are maybe uncertain of.