What defines the unit of measurement known as a joule?

The joule is defined as the amount of work done when a force of one newton acts over a distance of one meter in the direction of the force. This relationship highlights how energy is quantified in terms of the physical parameters of force and distance. When you apply a force to move an object, energy is transferred, and that energy transfer is what we measure in joules.

This definition is foundational in physics as it connects directly to the concepts of work and energy, allowing for a clear understanding of these principles in various contexts, including mechanics and thermodynamics. Options related to force multiplied by acceleration or mass times gravity do not capture the essence of the joule, as they pertain to different quantities in physics (like Newtons for force) rather than specifically defining work or energy directly. Energy used over time refers to power, not energy, which further distinguishes the proper definition of a joule.