Mechanical Aptitude Mechanical Aptitude Ultimate 3 — Questions and Answers
Question 1: A fixed pulley attached to the ceiling is used to lift a 200 lb load. How much force must be applied to the rope?
- 200 lbs (Correct answer)
- 100 lbs
- 400 lbs
- 50 lbs
Correct answer: 200 lbs
A single fixed pulley only changes the direction of force, not the magnitude, so you still need 200 lbs of pull.
Question 2: What causes a steel bridge to have expansion joints?
- Steel expands and contracts with temperature changes (Correct answer)
- Steel rusts and needs space to corrode
- Traffic vibration requires movement gaps
- Foundation settling creates uneven surfaces
Correct answer: Steel expands and contracts with temperature changes
Steel expands when heated and contracts when cooled; expansion joints accommodate this dimensional change and prevent buckling or cracking.
Question 3: In a V-belt drive system, what is the main advantage of a V-belt over a flat belt?
- Wedging action in the groove increases friction and reduces slipping (Correct answer)
- V-belts are lighter and cheaper to manufacture
- V-belts can operate at higher temperatures
- V-belts require less tensioning
Correct answer: Wedging action in the groove increases friction and reduces slipping
The V-shape wedges into the pulley groove, creating greater contact friction and allowing more torque transmission with less slipping.
Question 4: A screw with a pitch of 0.05 inches is turned 10 full rotations. How far does it advance linearly?
- 0.5 inches (Correct answer)
- 0.05 inches
- 5 inches
- 0.005 inches
Correct answer: 0.5 inches
Linear advance = pitch × number of rotations = 0.05 × 10 = 0.5 inches.
Question 5: Which valve type is best suited for fully open or fully closed service (not for throttling)?
- Gate valve (Correct answer)
- Needle valve
- Globe valve
- Ball valve
Correct answer: Gate valve
Gate valves are designed for isolation service (fully open or closed) because throttling causes erosion of the gate and seat.
Question 6: Two gears mesh together. Gear A has 15 teeth and Gear B has 45 teeth. If Gear A drives Gear B, what is the torque multiplication factor?
- 3× (Correct answer)
- 1/3×
- 1×
- 9×
Correct answer: 3×
Torque ratio = driven teeth / driver teeth = 45/15 = 3, so the output torque is tripled at the cost of reduced speed.
Question 7: A steel rod is heated until it glows red and then quickly plunged into cold water. This process is called:
- Quenching (Correct answer)
- Annealing
- Tempering
- Normalizing
Correct answer: Quenching
Quenching is the rapid cooling of heated metal in water, oil, or air to harden it by locking in a martensitic structure.
Mechanical Aptitude Mechanical Aptitude Ultimate 3
A fixed pulley attached to the ceiling is used to lift a 200 lb load.
How much force must be applied to the rope?