Air motor thermodynamics: An air motor operates on a cycle that is the reverse of the reciprocating air compressor cycle, expanding compressed air to produce work.

Introduction / Context:
Air motors and air compressors are thermodynamic inverses. Where compressors consume shaft work to raise air pressure, air motors use stored compressed air to deliver shaft work. Recognizing the reversed indicator diagrams improves understanding of pneumatic power systems.

Given Data / Assumptions:

• Reciprocating cylinder with valves arranged for intake of high-pressure air and exhaust of low-pressure air.
• Idealized processes comparable to those of reciprocating compressors but in reverse order.
• Friction and throttling losses exist but are secondary to the conceptual reversal.

Concept / Approach:
On a p–v diagram, a compressor follows a compression path from low to high pressure, rejecting heat or not depending on the process. An air motor follows the reverse: it admits high-pressure air, expands it to produce work, and exhausts at a lower pressure. Thus the air motor cycle is the time-reversed counterpart of the compressor cycle.

Step-by-Step Solution:

Verification / Alternative check:
Indicator diagrams from laboratory setups show mirrored loops for compressor and air motor when plotted under similar scaling, confirming the reversed nature.

Why Other Options Are Wrong:
Disagree and conditional statements are misleading. While real devices deviate from ideal paths, the fundamental thermodynamic relationship remains that an air motor cycle is the reverse of a compressor cycle.

Common Pitfalls:
Expecting identical efficiencies when reversing. Practical air motors have throttling losses and cannot exactly retrace the compressor path.

Final Answer:
Agree