ASVAB Mechanical Comprehension Test 3 — Questions and Answers
Question 1: A hydraulic jack uses a small piston with area 2 in² and a large piston with area 20 in². If you apply 50 lbs of force to the small piston, what force does the large piston exert?
- 250 lbs
- 500 lbs (Correct answer)
- 1000 lbs
- 100 lbs
Correct answer: 500 lbs
Pascal's Law states force is multiplied by the ratio of areas: 50 × (20/2) = 500 lbs.
Question 2: A wrench handle is 12 inches long. A second wrench handle is 18 inches long. How much more torque does the longer wrench produce with the same force?
- 1.5 times more (Correct answer)
- 2 times more
- 6 inch-pounds more
- The same amount
Correct answer: 1.5 times more
Torque = force × distance; 18/12 = 1.5, so the longer wrench produces 1.5 times the torque.
Question 3: Two gears mesh together. Gear A has 10 teeth and Gear B has 40 teeth. If Gear A spins at 200 RPM, how fast does Gear B spin?
- 800 RPM
- 50 RPM (Correct answer)
- 100 RPM
- 400 RPM
Correct answer: 50 RPM
Gear speed is inversely proportional to tooth count: 200 × (10/40) = 50 RPM.
Question 4: A spring with a spring constant of 8 N/m is compressed 0.5 m. How much potential energy is stored?
- 4 J
- 2 J
- 1 J (Correct answer)
- 8 J
Correct answer: 1 J
Elastic potential energy = ½kx² = ½ × 8 × 0.25 = 1 J.
Question 5: A wheel and axle system has a wheel radius of 15 cm and an axle radius of 3 cm. What is the mechanical advantage?
- 3
- 5 (Correct answer)
- 12
- 18
Correct answer: 5
Mechanical advantage of a wheel and axle = wheel radius / axle radius = 15/3 = 5.
Question 6: Which type of beam experiences the greatest bending stress when a load is applied at its center?
- A beam supported at both ends (Correct answer)
- A cantilever beam
- An arch beam
- A hollow beam
Correct answer: A beam supported at both ends
A simply supported beam with a center load experiences maximum bending moment at the center.
Question 7: A ball rolls down a ramp without slipping. At the bottom, its energy is divided between translational and rotational kinetic energy. Which statement is TRUE?
- All energy is translational
- A sliding block reaches the bottom faster than a rolling ball of equal mass (Correct answer)
- A rolling ball reaches the bottom faster than a sliding block
- Rotational energy has no effect on speed
Correct answer: A sliding block reaches the bottom faster than a rolling ball of equal mass
A sliding frictionless block converts all potential energy to translational KE, while a rolling ball splits energy into rotational KE, making it slower.
ASVAB Mechanical Comprehension Test 3
A hydraulic jack uses a small piston with area 2 in² and a large piston with area 20 in².
If you apply 50 lbs of force to the small piston, what force does the large piston exert?