Question 16Motor Plants - Assistant Engineer

The correct answer is A) rotating drum. The indicator card shown in the illustration is produced with a rotating drum. This type of indicator uses a rotating drum to record the pressure-volume diagram of an engine cylinder, which is a key component in evaluating the performance and efficiency of the engine. The rotating drum allows the indicator to capture the changes in pressure and volume over the course of the engine cycle, providing valuable data for the Coast Guard Captain's License Examination. The other options are incorrect because a sliding camshaft, oscillating drum, and balanced-diaphragm indicator are not the mechanisms used to produce the indicator card shown in the illustration.