ASVAB Mechanical Comprehension 3 — Questions and Answers
Question 1: A cam converts which type of motion into another?
- Linear to rotary
- Rotary to oscillating/linear (Correct answer)
- Oscillating to circular
- Circular to hydraulic
Correct answer: Rotary to oscillating/linear
A cam converts rotary motion into reciprocating or oscillating linear motion via a follower.
Question 2: Two objects of different masses are dropped from the same height in a vacuum. Which hits the ground first?
- The heavier object
- The lighter object
- They hit at the same time (Correct answer)
- Depends on their shape
Correct answer: They hit at the same time
In a vacuum, gravity accelerates all objects equally regardless of mass, so both hit simultaneously.
Question 3: Which material is the best conductor of heat?
- Wood
- Glass
- Copper (Correct answer)
- Rubber
Correct answer: Copper
Copper has a very high thermal conductivity, making it the best heat conductor among these options.
Question 4: A driver gear with 40 teeth meshes with a driven gear with 10 teeth. If the driver turns at 100 RPM, what is the speed of the driven gear?
- 25 RPM
- 100 RPM
- 200 RPM
- 400 RPM (Correct answer)
Correct answer: 400 RPM
Speed ratio is inverse of tooth ratio: 100 × (40/10) = 400 RPM.
Question 5: Which class of lever has the fulcrum located between the effort and the load?
- First class (Correct answer)
- Second class
- Third class
- Fourth class
Correct answer: First class
A first-class lever (like a seesaw or crowbar) has the fulcrum between effort and load.
Question 6: A belt connecting two pulleys slips when the tension difference between tight and slack sides is too great. What is the most effective fix?
- Increase pulley diameter
- Increase belt tension (Correct answer)
- Reduce load
- Use a shorter belt
Correct answer: Increase belt tension
Increasing belt tension raises friction force, allowing greater torque transfer without slipping.
Question 7: An object moving in a circle at constant speed has which type of acceleration?
- No acceleration
- Tangential acceleration
- Centripetal acceleration directed inward (Correct answer)
- Centrifugal acceleration directed outward
Correct answer: Centripetal acceleration directed inward
Centripetal acceleration is always directed toward the center of the circle, causing the direction change.
ASVAB Mechanical Comprehension 3
A cam converts which type of motion into another?