Which action is appropriate when the simulator’s paddle is not spinning?

The appropriate action when the simulator’s paddle is not spinning is to turn the machine on and off again. This process can help reset the internal systems, which might fix minor glitches that prevent the paddles from functioning properly. It's a fundamental troubleshooting step that can resolve a variety of operational issues in electronic devices, including breath alcohol testing equipment.

Turning the machine off and then back on can clear errors that may have occurred during operation and restore normal functionality. This step is often recommended for most technical problems before attempting more complex solutions or replacements.

While restarting the simulator and changing paddles might also be necessary actions under certain conditions, they are typically considered after a simple restart doesn't resolve the issue. Calibration is a separate process that ensures the machine is providing accurate readings, and it would not address the immediate problem of the paddle not spinning.