Final answer:
In virtual reality systems, a motion tracker or motion capture system records the user's foot movements to create an immersive experience.
Step-by-step explanation:
The component of a virtual reality system that is an input device designed to capture and record the movements of the user's feet as the user turns in different directions is known as a motion tracker or motion capture system. These systems often use sensors or cameras to detect and measure the movement and orientation of the user's body parts within the virtual environment. In such setups, the motion tracker is crucial for creating an immersive experience where actions in the physical world are accurately replicated in the virtual space.