Which component of the system performs the actual work of carrying the load?

• A. Generator
• B. Reservoir
• C. Check valve
• D. Hydraulic cylinder

Answer: (D)

The hydraulic cylinder is the actuator that actually applies the force to move the load. Pressure from the hydraulic fluid pushes on the piston inside the cylinder, and the resulting force (pressure times piston area) drives the piston rod to extend or retract. That linear motion directly carries and moves the load, converting hydraulic energy into mechanical work. The other components have supporting roles: a pump or generator supplies the energy to pressurize the fluid, the reservoir stores excess fluid, and the check valve controls flow and prevents backflow. None of those directly exert the load, so the cylinder is the part that does the work.