Describe the function of a solenoid in a mechanical system.

A solenoid functions by converting electrical energy into linear mechanical motion. When an electric current passes through the solenoid's coil, it generates a magnetic field, which then draws a movable iron core (or plunger) into the coil. This movement creates linear motion, which can be harnessed to perform work—like opening a valve, engaging a switch, or actuating another mechanical component.

The significance of a solenoid lies in its ability to transform electrical signals into mechanical actions, making it a crucial component in various automated and control systems where precise movement is required. This principle is utilized in many applications, from automotive to industrial machinery, demonstrating the versatility and importance of solenoids in modern mechanical systems. The other options, while related to mechanical systems, do not accurately describe the fundamental operation of a solenoid.