Mechanical Comprehension
Levers, pulleys, gears, and fluid systems — classic applied physics, delivered adaptively as the final subtest of the battery.
- Questions
- Adaptive
- Time limit
- 15 min
- Format
- No going back
- Counts toward
- SIFT score
See what the test looks like
Here are sample questions from our SIFT Mechanical Comprehension practice tests. Each question comes with a detailed explanation so you understand the reasoning, not just the answer.
What is the Mechanical Comprehension subtest?
Mechanical Comprehension (MCT) tests your understanding of mechanical and physical principles. Like Math Skills, it's a Computer Adaptive Test (CAT) that adjusts difficulty based on your performance. Answer correctly and questions get harder; answer incorrectly and they get easier.
The test covers simple machines (levers, pulleys, gears), force and motion (Newton's laws, gravity, friction), fluid dynamics (pressure, hydraulics, Bernoulli's principle), and basic electricity and thermodynamics. Many questions include diagrams showing mechanical systems — gear trains, pulley setups, lever configurations, or hydraulic circuits.
Because it's adaptive, the number of questions varies — typically 15–25 questions in approximately 15 minutes. Early questions establish your baseline difficulty level, so they have outsized influence on your score. Strong performers will see advanced physics questions; those struggling will see more basic mechanical concepts.
Mechanical Comprehension is one of seven subtests that collectively produce your SIFT score (scored 20–80). The SIFT is a computerized test required for all U.S. Army aviation candidates.
Key detail
Mechanical Comprehension is adaptive (CAT). You cannot skip questions or go back. Each correct answer raises difficulty; each wrong answer lowers it. Your score reflects the difficulty level you sustained, not just the number correct.
What the questions are made of
Mechanical Comprehension assesses understanding of mechanical and physical principles essential for aviation systems.
Simple Machines
Levers, pulleys, gears, inclined planes, wedges, and screws. Understand mechanical advantage, force multiplication, and how these machines change the direction or magnitude of force.
Force & Motion
Newton's laws, gravity, friction, acceleration, momentum, and work/energy concepts. These are the physics fundamentals behind how aircraft (and all machines) operate.
Fluid Dynamics
Pressure, hydraulics, pneumatics, Bernoulli's principle, and fluid behavior. Directly relevant to helicopter hydraulic systems, fuel systems, and aerodynamics.
Electrical & Thermal Basics
Simple circuits (series vs. parallel), voltage/current/resistance, heat transfer, and basic thermodynamic concepts. Army aircraft rely on complex electrical and thermal systems.
Tips & strategy
Mechanical comprehension tests conceptual understanding. If you understand WHY a lever provides mechanical advantage, you can answer any lever question. Memorizing specific answers won't help on an adaptive test.
Many questions include mechanical diagrams. Practice interpreting gear trains, pulley systems, lever setups, and hydraulic circuits from diagrams. Be comfortable extracting information visually.
Gears, levers, and pulleys appear most frequently. For gears: meshing gears turn opposite directions, larger gears turn slower but with more torque. For levers: know the three classes. For pulleys: count the ropes supporting the load.
Newton's three laws, work = force × distance, pressure = force / area, and conservation of energy cover most of the physics on this test. These principles apply to nearly every question.
Many questions can be answered by thinking about real-world experience: which way does a door swing, what happens when you step on a garden hose, how does a seesaw balance? Trust your physical intuition and then verify with principles.
Mechanical Comprehension, quick answers
What is the SIFT Mechanical Comprehension subtest?
Mechanical Comprehension (MCT) is a computer-adaptive test of mechanical concepts and simple machines. It adapts to your performance level: topics include simple machines, force and motion, and fluids. The clock does not adapt — the time limit is a fixed 15 minutes, and it is the number of questions that varies.
Is SIFT Mechanical Comprehension similar to the ASVAB version?
The concepts overlap significantly, but the SIFT version is computer-adaptive (CAT), meaning difficulty adjusts based on your answers. The SIFT may also include more advanced questions if you perform well, testing deeper physics and mechanical reasoning.
Do I need to know advanced physics?
No. The test starts at basic levels and only moves to advanced material if you're performing well. A solid understanding of high-school physics — Newton's laws, simple machines, and pressure — is sufficient for most candidates.
What resources should I use to study?
SIFT-specific prep books, the ASVAB Mechanical Comprehension study material (concepts overlap), and basic physics textbooks. Online physics simulations and mechanical reasoning practice tests are also highly effective.
Build your test-day method
- Exam-aligned drills under deliberate time pressure
- Instant explanations after every item
- Your score estimate, tracked drill after drill