What is the standard SI unit of energy, defined by the energy used when a force of one newton moves an object one meter?

The standard SI unit of energy is the joule, which is defined as the amount of energy transferred when a force of one newton is applied to move an object one meter in the direction of the force. This definition directly illustrates the relationship between force, distance, and energy, establishing the joule as a fundamental unit in both physics and chemistry.

While the watt is a unit of power (energy per unit time) and the calorie is a unit of heat energy, the joule specifically quantifies work done or energy transferred in mechanical contexts. The term "newton-meter" describes work and is mathematically equivalent to a joule, but it is not used as the standard unit of energy in the SI system; instead, the term joule consolidates this concept into a singular, widely recognized unit. These distinctions clarify the proper identification of joules as the correct answer.