Which hydraulic system component transforms power into mechanical force?

The correct answer is that the actuator is the component of a hydraulic system that transforms power into mechanical force. In hydraulic systems, an actuator can be a hydraulic cylinder or hydraulic motor that converts the hydraulic energy of pressurized fluid into mechanical motion. This transformation occurs when the hydraulic fluid, under pressure, pushes against a piston inside the actuator, resulting in linear or rotary movement which can perform work, such as lifting, pushing, or rotating an object.

This process is fundamental to how hydraulic systems function, as the actuator's role is to carry out the necessary mechanical tasks in response to the energy delivered by the hydraulic system. The hydraulic fluid serves as the medium that transmits pressure but does not itself perform work directly in terms of mechanical force. Similarly, while hydraulic pumps generate the flow and pressure necessary to move the fluid, they are not responsible for converting that energy into mechanical motion; that responsibility falls to the actuators themselves. The rotary gear, though it may be part of some hydraulic mechanisms, does not directly transform hydraulic power into mechanical force in the same way that actuators do.