WTMA Hydraulics and Fluid Dynamics 4

Question 1

Two hydraulic cylinders are connected in parallel to the same pump. Compared to a single cylinder, what is true about force and speed?

Accepted Answer

Force per cylinder is the same, but each extends at half the speed

Answer

In parallel, pressure (and thus force) is the same, but pump flow is split, so each cylinder extends more slowly.

Question 2

What happens to system pressure when a hydraulic cylinder reaches the end of its stroke and cannot move further?

Accepted Answer

Pressure rises until the relief valve opens

Answer

With no movement to absorb pump output, pressure builds rapidly until the relief valve opens to protect the system.

Question 3

Which factor most affects the viscosity of hydraulic oil in real-world operation?

Accepted Answer

Temperature

Answer

Viscosity drops significantly as temperature rises, which is why hydraulic systems specify oil grades for operating temperature ranges.

Question 4

A flow control valve is installed in a hydraulic circuit. Its primary function is to:

Accepted Answer

Regulate the speed of a hydraulic actuator

Answer

Flow control valves restrict or allow fluid flow to control actuator speed, not pressure or direction.

Question 5

Why is it important to bleed air from a hydraulic system?

Accepted Answer

Air is compressible and causes spongy, unpredictable actuator movement

Answer

Trapped air compresses under pressure, creating a cushioning effect that makes cylinder movement feel soft and inconsistent.

WTMA - Wiesen Test of Mechanical Aptitude Practice Test