NEIEP Mechanics Practice Exam

The correct choice highlights the essential components of a jack assembly, which are crucial for its operation. The head is integral as it connects the load to the jack and serves as the point of application for the force. The packing cylinder is designed to contain hydraulic fluid while preventing leaks, which is vital for maintaining pressure within the system. Finally, the plunger can move within the packing cylinder, allowing it to push hydraulic fluid and create the lifting action essential for the operation of the jack.

This configuration is fundamental because hydraulic jacks rely on the movement of the fluid driven by the plunger to lift heavy loads safely and efficiently. Understanding these components is key for anyone working with hydraulic systems, ensuring proper maintenance and effective troubleshooting.