🔍 Key Concepts

• Single-acting vs double-acting hydraulic cylinders – how many directions does hydraulic pressure act in? • How a single-acting ram returns/retracts – what brings it back after it is pushed out? • Difference between a pushing motion (extension) and a pulling motion (retraction) in hydraulics.

💭 Think About

• Think about where hydraulic oil under pressure is applied in a single-acting ram: is it on one side of the piston or on both? • Ask yourself: what usually causes the ram to come back in on a single-acting system (for example, gravity, a spring, or hydraulic pressure)? • Look at each choice and decide: does it describe pressure acting in one direction only, or in two directions? Which matches the word single-acting?

✅ Before You Answer

• Verify that single-acting means hydraulic pressure is applied on only one side of the piston/ram. • Check whether the ram’s retraction is done by hydraulic pressure or by some external force (spring, load, gravity). • Eliminate any options that describe pressure acting in two directions or that talk about a primary motion that doesn’t match how a single-acting ram normally works.