What is the primary function of a flywheel?

The primary function of a flywheel is to store rotational energy and maintain a steady output of motion. Flywheels are designed to resist changes in their rotational speed—when energy is added, they spin faster, and when energy is removed, they help sustain motion by releasing that stored energy gradually. This stability in the rotational speed allows for smoother operation of machines, especially in applications where consistent performance is critical, such as in engines or energy storage systems.

While the other options describe functions related to mechanical systems, they do not accurately capture the unique purpose of a flywheel. For instance, although storing energy is a factor in some contexts, the flywheel specifically deals with rotational rather than potential energy. Regulating fluid flow pertains more to hydraulic systems and does not relate to the operation of a flywheel. Additionally, while flywheels can provide support during acceleration, enhancing speed is not their primary function; instead, they focus on energy storage and stability.