ASVAB Mechanical Comprehension Principles 2 — Questions and Answers
Question 1: What type of lever has the fulcrum between the effort and the load?
- First-class lever (Correct answer)
- Second-class lever
- Third-class lever
- Compound lever
Correct answer: First-class lever
A first-class lever has the fulcrum between the effort (input force) and the load (output force). Examples include a seesaw, crowbar, and scissors.
Question 2: What happens to pressure when the area over which a force is applied decreases?
- Pressure increases (Correct answer)
- Pressure decreases
- Pressure stays the same
- Pressure becomes zero
Correct answer: Pressure increases
Pressure = Force ÷ Area. When the area decreases while force remains constant, pressure increases. This is why a sharp knife cuts better than a dull one — the same force is applied over a smaller area.
Question 3: A 200-pound object is lifted 6 feet using a lever with a mechanical advantage of 4. How much force is needed?
- 50 pounds (Correct answer)
- 100 pounds
- 25 pounds
- 200 pounds
Correct answer: 50 pounds
Force needed = Load ÷ Mechanical Advantage = 200 ÷ 4 = 50 pounds.
Question 4: What is torque?
- A rotational force applied at a distance from a pivot point (Correct answer)
- The speed at which an object rotates
- The weight of a rotating object
- The friction in a bearing
Correct answer: A rotational force applied at a distance from a pivot point
Torque is the rotational equivalent of force. It equals force multiplied by the distance from the pivot point (torque = force × lever arm). It causes objects to rotate.
Question 5: In a hydraulic system, what happens when pressure is applied to a confined fluid?
- The pressure is transmitted equally in all directions (Correct answer)
- The fluid compresses to half its volume
- The pressure is absorbed by the container walls
- The fluid only moves in one direction
Correct answer: The pressure is transmitted equally in all directions
Pascal's Law states that pressure applied to a confined fluid is transmitted undiminished in all directions. This principle is the basis for hydraulic systems used in brakes, lifts, and heavy machinery.
Question 6: What is the purpose of a governor on an engine?
- Regulate engine speed (Correct answer)
- Increase fuel efficiency
- Cool the engine
- Reduce exhaust emissions
Correct answer: Regulate engine speed
A governor is a mechanical device that automatically regulates engine speed by controlling fuel supply or throttle position. It prevents the engine from running too fast or too slow under varying loads.
ASVAB Mechanical Comprehension Principles 2
What type of lever has the fulcrum between the effort and the load?