Define "hydraulic power."

Hydraulic power is defined as the rate at which work is performed by a hydraulic system, which directly relates to the movement and control of hydraulic fluids within that system. This measure incorporates both the pressure of the hydraulic fluid and the flow rate, illustrating how efficiently the system can convert the energy from the fluid into mechanical work.

The correct answer emphasizes the importance of both force and motion in hydraulic systems. Hydraulic power is calculated using the formula:

[ \text{Power (P)} = \text{Pressure (P)} \times \text{Flow rate (Q)} ]

This indicates that to understand hydraulic power, one must consider not just the force exerted, but how quickly that force can be applied, representing the system’s overall effectiveness in doing work.

The other options, while related to aspects of hydraulic systems, do not encapsulate the full definition of hydraulic power. For example, the force exerted by a hydraulic cylinder relates to a single component's function rather than the system's power overall. The maximum pressure achievable is a characteristic of the system's limits rather than an operational parameter. The capacity of the fluid reservoir pertains to the storage of fluid, which does not inherently describe the performance of the hydraulic power itself.