WTMA Aptitude Knowledge 2 — Questions and Answers
Question 1: A pulley system has one fixed pulley and one movable pulley. How much force is needed to lift a 200 lb load?
- 200 lb
- 100 lb (Correct answer)
- 50 lb
- 400 lb
Correct answer: 100 lb
A system with one fixed and one movable pulley provides a mechanical advantage of 2, requiring 100 lb to lift a 200 lb load.
Question 2: Which type of gear is used to transmit motion between two shafts at a 90-degree angle?
- Spur gear
- Helical gear
- Bevel gear (Correct answer)
- Rack and pinion
Correct answer: Bevel gear
Bevel gears have angled teeth and are specifically designed to transmit motion between shafts that intersect at 90-degree angles.
Question 3: A lever with a 6-foot effort arm and a 2-foot resistance arm has a mechanical advantage of:
- 3 (Correct answer)
- 8
- 0.33
- 12
Correct answer: 3
Mechanical advantage of a lever equals effort arm length divided by resistance arm length: 6 ÷ 2 = 3.
Question 4: Water flows through a pipe that narrows from 4 inches to 2 inches in diameter. What happens to the water's speed?
- It halves
- It stays the same
- It doubles
- It quadruples (Correct answer)
Correct answer: It quadruples
By the continuity equation, when pipe area decreases by a factor of 4 (radius halved), velocity must increase by a factor of 4 to maintain flow rate.
Question 5: A spring stretched 3 inches by a 15 lb force is stretched how far by a 25 lb force?
- 3 inches
- 5 inches (Correct answer)
- 7 inches
- 10 inches
Correct answer: 5 inches
By Hooke's Law, spring constant = 15 ÷ 3 = 5 lb/in; 25 lb ÷ 5 lb/in = 5 inches of stretch.
Question 6: Which tool would best remove a stripped screw with a damaged head?
- Phillips screwdriver
- Torque wrench
- Screw extractor (Correct answer)
- Allen key
Correct answer: Screw extractor
A screw extractor bites into the stripped head using reverse-threaded action to turn and remove damaged screws.
Question 7: A circuit has a 12-volt battery and a 4-ohm resistor. The current flowing through it is:
- 48 amps
- 8 amps
- 3 amps (Correct answer)
- 0.33 amps
Correct answer: 3 amps
Using Ohm's Law: Current = Voltage ÷ Resistance = 12 ÷ 4 = 3 amps.
WTMA Aptitude Knowledge 2
A pulley system has one fixed pulley and one movable pulley.
How much force is needed to lift a 200 lb load?