Which unit measures energy or work in the MKS system?

In the MKS (Meter-Kilogram-Second) system, energy or work is measured in joules. A joule is defined as the amount of energy transferred when one newton of force is applied over one meter of distance. This relationship between force and distance is fundamental to understanding work in physics.

The joule provides a direct and standardized way to express energy, making it crucial in various fields, including physics and engineering. Understanding that the joule combines three basic physical quantities—force, distance, and mass—is key to its importance in energy calculations.

Other units mentioned serve different purposes. Horsepower measures power, which is the rate of doing work rather than the work itself. Newton is a unit of force rather than energy. Pascal measures pressure, which is force per unit area, not a measure of work or energy. Each of these units plays a specific role in the measurement system, but the joule is the one that specifically quantifies energy and work in the MKS system.