Mechanical Comprehension practice: ASVAB simple machines
Ten questions in two sets of five on levers, gears, pulleys, pressure, hydraulic jacks, ramps, work and the wheel and axle. One principle behind them all: what you save in force, you pay in distance.
Correct answers
0 / 5
0 of 5 answered: the explanations appear below as you go.
| Subtests covered | MC |
Practice items written by Radif Partners for this site, not real ASVAB questions. A share of correct answers does not convert into a standard score or an AFQT percentile.
Prepared by Radif Partners · Method · official sources read on October 22, 2026 · published formulas and tables
Mechanical Comprehension (MC) is the ASVAB subtest on simple machines and basic mechanics: levers, gears, pulleys, inclined planes, the wheel and axle, pressure, hydraulics and work. Most items are solved with one balance equation or one ratio. The computer version gives 15 questions in 22 minutes, about 88 seconds each, and the paper version 25 questions in 19 minutes, about 46 seconds each. MC is not part of the AFQT, but it reaches further than most technical subtests: it is part of the Air Force Mechanical area (AR + MC + AS + 2VE) and of 2 Marine Corps line scores, including GT (AR + MC + VE), the Marine Corps general technical score. A candidate with AR 52 and VE 54 who raises MC from 43 to 51 moves the Marine GT from 99 to 105 and the Mechanical percentile from 49 to 57. The ten questions are written by Radif Partners, not real ASVAB items, and a count of right answers is not a score.
What Mechanical Comprehension covers
The ten questions on this page touch every family of the subtest: a lever balancing a load, two gears with different tooth counts, three gears in a row, a block and tackle, pressure on an area, a hydraulic jack, a ramp, the work done lifting a box, a wheel and axle, and the class of lever a wheelbarrow belongs to. On the real test many items come with a drawing; here the setup is written out, which trains you to build the picture yourself. The Official ASVAB sample questions show the illustrated format.
Time per item
The Official ASVAB fact sheet gives MC 15 questions in 22 minutes on the computer test, about 88 seconds each, and 25 questions in 19 minutes on paper, about 46 seconds each. That is enough for one equation per item if you know which one to write. Spending two minutes reasoning from scratch on a pulley problem is the usual way to run out of time.
The one principle and its traps
Every simple machine trades force for distance: the work put in equals the work you get out, ignoring friction. Keep that in mind and most traps disappear.
- Levers. Force times distance must match on both sides of the fulcrum. A 150 pound load 2 feet from the fulcrum needs 50 pounds 6 feet away: 150 × 2 = 50 × 6. Choosing 450 means you multiplied instead of balancing.
- Gear speed. A 20 tooth gear at 120 rpm driving a 40 tooth gear turns it at 60 rpm, not 240. More teeth, slower turn, more turning force.
- Gear direction. In a row of three gears, the first and third turn the same way. Count: each mesh reverses.
- Pulleys and ramps. Four rope segments under 400 pounds mean a pull of 100 pounds. A 12 foot ramp rising 3 feet lets 60 pounds move a 240 pound crate, because the push covers four times the height.
- Hydraulics. Pressure is the same on both pistons, so force scales with area: 50 pounds on 2 square inches becomes 500 pounds on 20. The small piston travels ten times farther.
- Lever classes. First class has the fulcrum in the middle (a seesaw), second class the load in the middle (a wheelbarrow), third class the effort in the middle (tweezers).
Where MC counts
MC has no effect on the AFQT, yet it appears in 1 Air Force area, Mechanical, and in 2 Marine Corps line scores: MM = AR + MC + EI + AS; GT = AR + MC + VE. All of these come from the formulas of the 1997 score scale report. Take a Marine candidate with AR 52, VE 54, EI 49 and AS 50: the AFQT is 59 and the Army GT, which ignores MC, would be 106. With MC 43, the Marine GT is 99 and MM 96. With MC 51, they become 105 and 101, and the Air Force Mechanical percentile moves from 49 to 57. The Marine Corps page lists the line scores and what the Marine Corps recruiting site says about requirements; the line score calculator shows every composite at once.
How to prepare
Draw each machine as you study it, with the force, the load and the distances marked. Write the governing equation under each drawing: force × distance for levers, teeth ratio for gears, segments for pulleys, length over height for ramps, area ratio for hydraulics, force × distance for work. Then mix problems so you learn to recognize the machine before writing anything. Auto and Shop shares the Mechanical area and the Marine MM score with MC, so the Auto and Shop page is a natural partner, and the Electronics Information page completes MM. Check your balance across all subtests with the practice test.