The joule (J) is the SI derived unit of energy and work. It is named after James Prescott Joule, a British physicist who made significant contributions to the study of energy. One joule is equal to the work done by a force of one newton acting over a distance of one meter.
The joule is a very important unit in physics, as it is used to quantify the amount of energy involved in many different processes. For example, the energy of a moving object is given by the equation E = 1/2 mv^2, where E is the energy in joules, m is the mass of the object in kilograms, and v is the velocity of the object in meters per second. The joule is also used to measure the energy content of food, the efficiency of engines, and the power output of electrical devices.