What does a pneumatic system primarily use to perform work or transmit force?

A pneumatic system primarily relies on compressed air to perform work or transmit force. Compressed air acts as the medium for energy transfer in pneumatic applications, allowing for movement, driving of tools, or actuation of mechanisms. The use of air pressure enables the system to operate with lighter components compared to hydraulic systems, which use fluid.

In pneumatic systems, air is compressed in a reservoir and then released through valves to perform work on cylinders or other devices, facilitating movement. This method is particularly advantageous for applications that require rapid actuation and control, making it suitable for many automated processes in manufacturing and assembly.

The other options involve different principles: electricity pertains to electrical systems; hydraulic fluid is used in hydraulic systems which rely on liquids for force transmission; while mechanical gears transfer motion rather than directly providing a medium for force or work. Therefore, compressed air is the essential element that defines the operation of pneumatic systems.