Plant Operator Selection System Test Plant Operator Selection System Mechanical Concepts 2

Question 1

A pump is operating at 1,800 RPM and moves 50 gallons per minute. If the speed is increased to 3,600 RPM, approximately how much fluid will the pump move per minute?

Accepted Answer

100 gallons

Answer

Pump flow rate is directly proportional to shaft speed, so doubling RPM doubles the flow rate from 50 to 100 GPM.

Question 2

Which type of valve is best suited for completely stopping or fully opening flow in a pipeline, but is NOT recommended for throttling?

Accepted Answer

Gate valve

Answer

Gate valves are designed for fully open or fully closed service and can be damaged if used to throttle flow.

Question 3

A wrench with a 12-inch handle requires 30 lb of force to turn a bolt. What force would be needed if the handle were extended to 18 inches?

Accepted Answer

20 lb

Answer

Torque must remain constant, so force × distance = 30 × 12 = 360 lb-in; 360 ÷ 18 = 20 lb.

Question 4

In a hydraulic system, a small piston with an area of 2 sq in supports a large piston with an area of 20 sq in. If 10 lb is applied to the small piston, what load can the large piston support?

Accepted Answer

100 lb

Answer

Pascal's law states pressure is equal throughout, so 10 lb ÷ 2 sq in = 5 psi × 20 sq in = 100 lb.

Question 5

Which of the following best describes the purpose of a pressure relief valve in a piping system?

Accepted Answer

To prevent system pressure from exceeding a safe limit

Answer

A pressure relief valve automatically opens to vent excess pressure and protect equipment when system pressure exceeds a set point.

Plant Operator Selection System Test Practice Test

Plant Operator Selection System Test Practice Test

Plant Operator Selection System Test Plant Operator Selection System Mechanical Concepts 2