The unit of energy, the Joule, is commonly used in the MKS (meter-kilogram-second) system of units. In the MKS system, the Joule is defined as the amount of work done by a force of one Newton when it acts on an object and displaces it by a distance of one meter. This definition highlights the relationship between force, distance, and energy.
To understand why the Joule is considered an MKS unit, it’s important to briefly delve into the history of unit systems. The CGS (centimeter-gram-second) system was widely used before the introduction of the MKS system. In the CGS system, the unit of energy is the erg, which is defined as the amount of work done by a force of one dyne when it acts on an object and displaces it by a distance of one centimeter.
The erg and the Joule are related through a conversion factor: 1 Joule is equal to 10 million ergs. This conversion factor allows for easy conversion between the MKS and CGS systems when dealing with energy measurements.
However, it is important to note that the Joule is primarily associated with the MKS system, and it is the preferred unit of energy in scientific and engineering applications. The MKS system is commonly used in fields such as physics, mechanics, and engineering, where the measurement of energy is frequently encountered.
In my personal experience as a physics student, I have extensively used the Joule as the unit of energy in various calculations. Whether it was calculating the energy required to lift an object, the energy released in a chemical reaction, or the energy transferred in an electrical circuit, the Joule has been a fundamental unit in all these scenarios.
To summarize, the Joule is considered an MKS unit of energy. It is defined as the amount of work done by a force of one Newton when it displaces an object by a distance of one meter. Although there is a conversion factor between the MKS and CGS systems, the Joule is primarily associated with the MKS system and is widely used in scientific and engineering applications.