The SI unit of measurement for work is the joule (J). Work is defined as the energy transferred when a force is applied to an object, causing it to move. One joule is equivalent to the amount of work done when a force of one newton causes displacement of one meter in the direction of the force. The equation for calculating work is W = F × d, where W stands for work, F for force, and d for distance. Understanding work in joules is crucial in physics and engineering applications.