About Mechanical Comprehension

Mechanical Comprehension evaluates your understanding of basic mechanical and physical principles. Questions cover simple machines (levers, pulleys, gears, inclined planes), force and motion, fluid dynamics, and structural support concepts. On the CAT-ASVAB, you have approximately 20 minutes for 15 questions. This section requires both conceptual understanding and the ability to apply physics principles to practical situations. MC contributes to several important composite scores including MM (Mechanical Maintenance), CO (Combat), and FA (Field Artillery), making it essential for many military technical and combat roles.

Topics Covered

Simple Machines (Levers, Pulleys, Gears)
Inclined Planes & Wedges
Force, Work & Energy
Newton's Laws of Motion
Friction & Gravity
Fluid Mechanics & Hydraulics
Pressure & Pascal's Law
Structural Support & Load
Mechanical Advantage
Rotational Motion & Torque

Sample Questions

Sample Question 1
Which simple machine is a door handle (lever type) an example of?
  • Wheel and axle
  • Inclined plane
  • Wedge
  • Screw
A door handle works like a wheel and axle - the handle is the wheel (larger radius), the spindle is the axle.
Sample Question 2
Gear A has 20 teeth and meshes directly with Gear B which has 60 teeth. If Gear A rotates at 300 RPM, how fast does Gear B rotate?
  • 100 RPM
  • 300 RPM
  • 600 RPM
  • 900 RPM
Gear ratio = 20:60 = 1:3. Gear B speed = 300 × (20/60) = 100 RPM.
Sample Question 3
A 20-foot long plank is used as a lever. The fulcrum is 5 feet from one end. If a 100-pound weight is on the short end, how much force is needed on the long end to balance?
  • 25 lbs
  • 33.3 lbs
  • 50 lbs
  • 75 lbs
Balance: Weight × Distance = Force × Distance. 100 × 5 = Force × 15. Force = 500/15 = 33.3 lbs.

Study Tips for Mechanical Comprehension

Understand Mechanical Advantage

Know how simple machines multiply force. For levers, pulleys, and gears, understand the trade-off between force and distance.

Visualize the Problem

Many MC questions include diagrams. Practice reading mechanical diagrams and visualizing how forces act on objects.

Review Newton's Laws

Newton's three laws of motion are fundamental. Understand how they apply to everyday mechanical situations.