ExxonMobil Test Mechanical Aptitude 2 — Questions and Answers
Question 1: A centrifugal pump's flow rate is 500 GPM at 1,000 RPM. If the speed increases to 1,500 RPM, what is the new flow rate?
- 750 GPM (Correct answer)
- 1000 GPM
- 500 GPM
- 650 GPM
Correct answer: 750 GPM
Flow rate scales linearly with speed: 500 × (1,500/1,000) = 750 GPM.
Question 2: What does a pressure gauge reading of zero indicate when a system is known to be pressurized?
- A faulty or damaged gauge (Correct answer)
- The system is safe to open
- Pressure has been fully relieved
- Normal operating condition
Correct answer: A faulty or damaged gauge
A zero reading on a pressurized system signals a malfunctioning gauge that should be inspected before proceeding.
Question 3: In a hydraulic system, if the input piston area is 5 sq in and output piston area is 25 sq in, what output force is generated by a 100 lb input force?
- 500 lb (Correct answer)
- 20 lb
- 2,500 lb
- 100 lb
Correct answer: 500 lb
Pascal's Law: output force = input force × (output area / input area) = 100 × (25/5) = 500 lb.
Question 4: Which type of bearing is designed to support radial loads and resist rotation friction in rotating shafts?
- Ball bearing (Correct answer)
- Thrust bearing
- Sleeve bearing
- Needle bearing
Correct answer: Ball bearing
Ball bearings are the standard choice for supporting radial loads while reducing rotational friction.
Question 5: What is the primary purpose of a heat exchanger in a refinery?
- To transfer heat between two fluid streams without mixing them (Correct answer)
- To generate steam for power
- To filter impurities from crude oil
- To measure fluid temperature
Correct answer: To transfer heat between two fluid streams without mixing them
Heat exchangers transfer thermal energy between process streams while keeping the fluids separated.
Question 6: A drive belt connects two pulleys: driving pulley diameter 10 cm and driven pulley diameter 5 cm. If the drive pulley turns at 400 RPM, what is the driven pulley speed?
- 800 RPM (Correct answer)
- 200 RPM
- 400 RPM
- 1,600 RPM
Correct answer: 800 RPM
Speed ratio = drive diameter / driven diameter = 10/5 = 2; 400 × 2 = 800 RPM.
ExxonMobil Test Mechanical Aptitude 2
A centrifugal pump's flow rate is 500 GPM at 1,000 RPM.
If the speed increases to 1,500 RPM, what is the new flow rate?