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
A torque wrench requires 50 lb-ft to tighten a bolt. If the wrench is 2 feet long, how much force must be applied at the end?
  • 25 lbs
  • 50 lbs
  • 100 lbs
  • 200 lbs
Torque = Force × Distance. 50 = Force × 2, so Force = 25 lbs.
Sample Question 2
When a weight is lifted by a single fixed pulley, the force required is:
  • Half the weight
  • Equal to the weight
  • Twice the weight
  • One quarter the weight
A single fixed pulley only changes the direction of force. It offers no mechanical advantage (MA=1).
Sample Question 3
In a hydraulic system, piston A has area 2 sq in and piston B has area 10 sq in. If 50 lbs force is applied to piston A, what force is exerted by piston B?
  • 10 lbs
  • 50 lbs
  • 100 lbs
  • 250 lbs
Pascal's Law: F₂/F₁ = A₂/A₁. F₂ = 50 × (10/2) = 250 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.