ASVAB Mechanical Comprehension Principles 1 — Questions and Answers
Question 1: A lever has a fulcrum in the center. If you push down on one end, what happens to the other end?
- It goes up (Correct answer)
- It stays in place
- It also goes down
- It moves sideways
Correct answer: It goes up
A lever pivots around its fulcrum. When one end is pushed down, the other end rises. This is the basic principle of a first-class lever, like a seesaw.
Question 2: What is the mechanical advantage of a pulley system with 4 supporting ropes?
- 4 (Correct answer)
- 2
- 8
- 1
Correct answer: 4
The mechanical advantage of a pulley system equals the number of rope sections supporting the load. With 4 supporting ropes, the mechanical advantage is 4, meaning you only need 1/4 the force.
Question 3: Which simple machine is a ramp an example of?
- Inclined plane (Correct answer)
- Lever
- Wheel and axle
- Screw
Correct answer: Inclined plane
A ramp is an inclined plane, one of the six simple machines. It reduces the force needed to raise an object by increasing the distance over which the force is applied.
Question 4: What is friction?
- A force that opposes motion between surfaces in contact (Correct answer)
- A force that causes objects to accelerate
- The energy stored in a compressed spring
- The tendency of objects to fall due to gravity
Correct answer: A force that opposes motion between surfaces in contact
Friction is a force that resists the relative motion of surfaces in contact. It can be helpful (allowing you to walk without slipping) or harmful (causing wear on machine parts).
Question 5: If a gear with 20 teeth meshes with a gear with 40 teeth, and the smaller gear turns at 100 RPM, how fast does the larger gear turn?
- 50 RPM (Correct answer)
- 100 RPM
- 200 RPM
- 25 RPM
Correct answer: 50 RPM
Gear ratio = 20/40 = 1/2. The larger gear turns at half the speed: 100 × (20/40) = 50 RPM. Larger gears turn slower when driven by smaller ones.
Question 6: What does Newton's First Law of Motion state?
- An object at rest stays at rest unless acted on by an external force (Correct answer)
- Force equals mass times acceleration
- Every action has an equal and opposite reaction
- Energy cannot be created or destroyed
Correct answer: An object at rest stays at rest unless acted on by an external force
Newton's First Law (Law of Inertia) states that an object at rest remains at rest, and an object in motion remains in motion at constant velocity, unless acted upon by a net external force.
ASVAB Mechanical Comprehension Principles 1
A lever has a fulcrum in the center.
If you push down on one end, what happens to the other end?