Which statement best summarizes the difference between hydraulic and pneumatic cylinders?

• A. Pneumatic cylinders use gas and respond quickly but are not as powerful.
• B. Hydraulic cylinders use liquid, are more powerful, but slower to react.
• C. Hydraulic cylinders are faster to react than pneumatic.
• D. Pneumatic cylinders use liquids.

Answer: (B)

The main idea is how the fluid used in the cylinder affects force and speed. Hydraulic cylinders rely on a liquid under pressure, which makes them capable of producing very large forces because liquids are hardly compressible and can transfer energy efficiently through the system. That power comes with a trade-off: the motion tends to be slower and more controlled due to fluid dynamics, valve restrictions, and pump flow.

Pneumatic cylinders use a gas, which is compressible, so energy is released quickly and they respond fast, but the achievable force is lower and often less precise. So the statement that hydraulic cylinders use liquid, are more powerful, but slower to react best captures this difference.

The other options either misstate the fluid (pneumatic signs as using liquids) or the speed/power relationship (hydraulic being faster, or pneumatic being inherently slow), so they don’t fit as well.