Mechanical Aptitude Mechanical Aptitude Principles 4 — Questions and Answers
Question 1: A screwdriver with a handle diameter of 3 inches turns a screw with shaft diameter of 0.5 inches. What is the mechanical advantage?
- 1.5
- 6 (Correct answer)
- 3
- 0.5
Correct answer: 6
MA of a wheel and axle = radius of wheel / radius of axle = 1.5 / 0.25 = 6.
Question 2: Which of the following materials is the BEST conductor of heat?
- Wood
- Rubber
- Copper (Correct answer)
- Glass
Correct answer: Copper
Copper has high thermal conductivity and is widely used in heat exchangers and cookware.
Question 3: A drive belt connects a 6-inch pulley to a 3-inch pulley. If the larger pulley turns at 200 RPM, how fast does the smaller pulley turn?
- 100 RPM
- 400 RPM (Correct answer)
- 300 RPM
- 600 RPM
Correct answer: 400 RPM
Speed ratio is inverse of diameter ratio: 200 × (6/3) = 400 RPM.
Question 4: What does a torque wrench measure?
- The linear force applied to a bolt
- The rotational force applied to a fastener (Correct answer)
- The angle of a nut
- The speed of rotation
Correct answer: The rotational force applied to a fastener
A torque wrench measures the rotational force (torque) applied to a fastener to ensure proper tightening.
Question 5: In a closed container, if the temperature of a gas doubles (in Kelvin) while volume stays constant, what happens to pressure?
- Pressure halves
- Pressure stays the same
- Pressure doubles (Correct answer)
- Pressure quadruples
Correct answer: Pressure doubles
Gay-Lussac's Law states pressure is directly proportional to temperature at constant volume: doubling T doubles P.
Question 6: Which gear type is used when the two shafts are at right angles to each other?
- Spur gear
- Helical gear
- Bevel gear (Correct answer)
- Rack gear
Correct answer: Bevel gear
Bevel gears are cone-shaped and designed to transmit power between shafts that intersect at an angle, typically 90°.
Question 7: A circuit has a 12V battery and a 4-ohm resistor. What is the current flowing through the circuit?
- 48 A
- 8 A
- 3 A (Correct answer)
- 0.33 A
Correct answer: 3 A
Ohm's Law: I = V / R = 12 / 4 = 3 amperes.
Mechanical Aptitude Mechanical Aptitude Principles 4
A screwdriver with a handle diameter of 3 inches turns a screw with shaft diameter of 0.5 inches.
What is the mechanical advantage?