The joule is a unit of work.
The term joule , or joule , is used in the field of physics to refer to a unit of work that is part of the international system. One joule is equivalent to the work produced by a constant force of one newton whose point of application travels one meter in the same direction of the force .
To understand what a joule is, therefore, it is important to first know what various concepts consist of. In physics, work is the product of a force and the distance traveled by its point of application. In other words: when a force modifies the state of motion of a body, it does work.
A newton , meanwhile, is a unit of force. One newton is equivalent to the force that produces an acceleration of 1 meter/second every second when applied to a body with a mass of one kilogram.
What is a joule
Combining the concepts of work , force and newton , we then arrive at the idea of joule, whose symbol is J. The formal definition indicates that a force of 1 newton with a point of application that moves one meter in the same direction of the force does an amount of work of 1 joule .
It is essential to keep in mind that, for theoretical purposes, the various resistances are not considered. That is why when measuring the work of force, the influence of air friction, for example, is not analyzed.
It should be noted that joule comes from James Prescott Joule . This English physicist, born in 1818 and died in 1889 , made great discoveries linked to energy , electricity, magnetism and thermodynamics.
Different equivalences
When solving problems, it is very important to know the equivalences of the different units used, since the possibility of solving an unknown and finding out its value often depends on this resource. In the case of the joule, the list is quite extensive. We can say, therefore, that one joule is equivalent to: one newton per meter; one watt per second; 6.2415 times 10 to the 18th electron volt; one coulomb per volt; 0.00987 atmosphere per liter; one pascal per cubic meter; 0.238902957 calorie.
As we can see, there are many units that are related to the joule, and some are not so common outside the field of physics. The electronvolt , for example, is the unit of energy that serves to represent a kinetic energy variation that an electron goes through when it moves between two points of different potentials (which are usually designated Va and Vb), provided that the difference between both be one volt.
It is estimated that one joule is the energy required to throw an apple 1 meter upwards.
The coulomb , on the other hand, is a unit derived from the international system and is used to measure the physical quantity known as electric charge or quantity of electricity . Its name also derives from a physicist, this case from the Frenchman Charles-Augustin de Coulomb . The definition of the coulomb is the following: it is the amount of charge that a current of one ampere carries in one second.
The joule and inverse equivalences
These equivalences are measured taking into account 1 joule, but there are also others called inverses , in which the value 1 is given to the other units . Let's look at some of them below: One watt per hour is equivalent to 3600 joules; one kilowatt hour is equal to 3.6 times 10 to the power of 6 joules; one calorie is equivalent to 4,187 joules; One kilocalorie, given that it is one thousand calories, is equal to 4187 joules.
Physics also uses everyday examples to graph some of its concepts. In the case of a joule, it is estimated that it is: the energy used when throwing a small apple upward so that it rises one meter ; the energy that is released when said apple falls.