Which of the following is true about the law of conservation of energy in fluids?

The law of conservation of energy states that within a closed system, energy cannot be created or destroyed, but can only change forms. In the context of fluids, this principle asserts that the total energy within a closed fluid system—including kinetic energy (energy of motion), potential energy (energy stored due to position), and internal energy (due to the temperature of the fluid)—remains constant unless acted upon by an external force.

When considering fluid dynamics, the energy conservation principle can be expressed through Bernoulli's equation, which correlates the pressure, velocity, and height of a fluid in steady, incompressible flow. According to this equation, as one form of energy (such as kinetic) increases, another form (like potential) must decrease, ensuring that the total energy remains constant throughout the system.

This understanding is essential for analyzing various scenarios in fluid mechanics, such as flow in pipes, atmospheric movements, and hydraulic systems, where it is crucial to account for energy transformations rather than creation or destruction of energy. Therefore, the assertion that energy is conserved in a closed fluid system is consistent with core principles of physics and fluid mechanics.