Which law states that energy cannot be created or destroyed, only transformed?

The statement that energy cannot be created or destroyed, only transformed, is a fundamental principle captured by the Law of Conservation of Energy. This law emphasizes that while energy can change forms – for example, from kinetic energy to potential energy, or from thermal energy to mechanical energy – the total amount of energy in a closed system remains constant.

This principle is foundational in physics and underpins many scientific concepts and applications. It helps explain phenomena in various fields, from mechanics to thermodynamics, and reinforces the idea that energy transformations are a natural part of physical processes. Understanding this law allows scientists to predict how energy will behave in different scenarios, whether it be in an engine, a roller coaster, or even in biological systems.

While the First Law of Thermodynamics is indeed another name for the law specifically applied to thermodynamic processes, the broader term "Law of Conservation of Energy" is widely used in many contexts beyond just thermodynamics. Thus, emphasizing the conservation aspect makes it applicable across different disciplines.