Mechanical Aptitude Mechanical Aptitude Principles 2 — 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 on the small piston, what force does the large piston exert?
- 100 lbs
- 500 lbs (Correct answer)
- 250 lbs
- 1000 lbs
Correct answer: 500 lbs
Pascal's Law states force is multiplied by the ratio of piston areas: 50 × (20/2) = 500 lbs.
Question 2: Which type of gear changes rotational motion into linear motion?
- Bevel gear
- Worm gear
- Rack and pinion (Correct answer)
- Planetary gear
Correct answer: Rack and pinion
A rack and pinion converts the rotary motion of the pinion into the linear motion of the rack.
Question 3: A 10-foot board is balanced on a fulcrum. A 200 lb person sits 2 feet from the fulcrum. How far from the fulcrum must a 100 lb person sit to balance?
- 2 feet
- 4 feet (Correct answer)
- 6 feet
- 8 feet
Correct answer: 4 feet
Torque balance: 200 × 2 = 100 × d, so d = 4 feet.
Question 4: What happens to the pressure in a fluid when its velocity increases through a constriction?
- Pressure increases
- Pressure decreases (Correct answer)
- Pressure stays the same
- Pressure doubles
Correct answer: Pressure decreases
Bernoulli's principle states that as fluid velocity increases, its pressure decreases.
Question 5: A wedge is used to split a log. The wedge has a narrow angle. Compared to a wide-angle wedge, the narrow wedge requires:
- More force but travels farther
- Less force but travels farther (Correct answer)
- More force and less distance
- The same force
Correct answer: Less force but travels farther
A narrower wedge angle provides greater mechanical advantage, requiring less force over a longer stroke.
Question 6: Two gears are meshed together. Gear A has 12 teeth and Gear B has 36 teeth. If Gear A spins at 300 RPM, how fast does Gear B spin?
- 900 RPM
- 150 RPM
- 100 RPM (Correct answer)
- 75 RPM
Correct answer: 100 RPM
Speed ratio is inverse of tooth ratio: 300 × (12/36) = 100 RPM.
Question 7: Which property of a material describes its ability to return to its original shape after a force is removed?
- Plasticity
- Ductility
- Elasticity (Correct answer)
- Brittleness
Correct answer: Elasticity
Elasticity is the property that allows a material to recover its original shape after deformation.
Mechanical Aptitude Mechanical Aptitude Principles 2
A hydraulic jack uses a small piston with area 2 in² and a large piston with area 20 in².
If you apply 50 lbs on the small piston, what force does the large piston exert?