ASVAB Mechanical Comprehension: Tips and Practice
Updated October 27, 2026
Mechanical Comprehension has 15 scored questions on the CAT-ASVAB. It doesn’t count toward your AFQT, but it’s part of the line scores for many mechanical and technical military jobs. Most questions come down to a few simple machines and one idea: mechanical advantage, trading distance for force. Here’s what to know, followed by free practice questions.
Levers
Effort × effort distance = load × load distance (distances are measured from the fulcrum).
The farther from the fulcrum you push, the less force you need.
Pulleys
The mechanical advantage of a pulley system is about equal to the number of rope sections supporting the load. With 4 supporting sections, you lift a 200-pound load with about 50 pounds of force, but you pull 4 times as much rope.
Gears
- Gears that mesh turn in opposite directions.
- A smaller gear driven by a larger one turns faster.
- Speed ratio: driver teeth ÷ driven teeth. A 40-tooth gear driving a 20-tooth gear makes the smaller gear turn twice as fast.
Inclined planes
A longer, gentler ramp needs less force to push a load up, over a longer distance.
Mechanical advantage = ramp length ÷ ramp height.
Tips
- Picture the motion in your head or sketch it.
- Remember the trade-off: less force always means more distance.
- In gear trains, count the gears to work out direction: every other gear turns the same way.
Free Mechanical Comprehension practice questions
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A lever has its fulcrum 2 feet from a 100-pound load. How much force is needed 8 feet from the fulcrum on the other side to balance it?Answer: AEffort × 8 = 100 × 2, so effort = 200 ÷ 8 = 25 pounds.
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Gear A turns clockwise and meshes directly with gear B. Which way does gear B turn?Answer: BGears that mesh directly turn in opposite directions.
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A 30-tooth gear drives a 10-tooth gear. If the 30-tooth gear turns once, how many times does the 10-tooth gear turn?Answer: CThe speed ratio is driver teeth ÷ driven teeth = 30 ÷ 10 = 3, so the smaller gear turns 3 times.
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A pulley system has 4 rope sections supporting a 240-pound load. About how much force is needed to lift it?Answer: BThe mechanical advantage is about 4, so the force needed is 240 ÷ 4 = 60 pounds.
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Which ramp needs the least force to push a box up to a 3-foot-high platform?Answer: DA longer ramp to the same height has a greater mechanical advantage (length ÷ height), so it needs the least force, though you push the box farther.
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Three gears are in a row, each meshing with the next. The first gear turns clockwise. Which way does the third gear turn?Answer: CEach meshing gear reverses direction: the second turns counterclockwise, so the third turns clockwise again.
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A first-class lever has the fulcrum between the effort and the load. Which tool is an example?Answer: BA seesaw has its pivot between the two ends. A wheelbarrow is a second-class lever (load in the middle), and tweezers and fishing rods are third-class levers (effort in the middle).
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A single fixed pulley at the top of a flagpole mainly:Answer: CA single fixed pulley has a mechanical advantage of 1. It doesn't reduce the force, but lets you pull down to lift the flag up.
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A wheel and axle has a wheel radius of 12 inches and an axle radius of 2 inches. What is its mechanical advantage?Answer: BMechanical advantage of a wheel and axle = wheel radius ÷ axle radius = 12 ÷ 2 = 6.
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Which simple machine is a screw a form of?Answer: DA screw's thread is an inclined plane wrapped around a shaft, which turns a small turning force into a strong straight-line force.
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Water flows through a pipe that narrows from a wide section to a narrow section. In the narrow section, the water:Answer: AThe same volume of water must pass through each section every second, so it speeds up where the pipe is narrower.
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A gear with 12 teeth drives a gear with 36 teeth. How does the larger gear turn compared with the smaller one?Answer: BSpeed ratio = driver teeth ÷ driven teeth = 12 ÷ 36 = 1/3, so the larger gear turns at one-third the speed (with more turning force).
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Two springs are identical. One is compressed twice as far as the other. Compared with the first spring, how much force does it exert?Answer: CFor a spring within its normal range, force is proportional to how far it's compressed or stretched, so twice the compression gives twice the force.
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A load is lifted with a block and tackle that has 3 supporting rope sections. To raise the load 2 feet, how far must you pull the rope?Answer: DWith 3 supporting sections, you pull 3 feet of rope for every 1 foot the load rises: 2 × 3 = 6 feet.
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Which is the best way to make a heavy box easier to drag across the floor?Answer: DRollers or wheels replace sliding friction with much lower rolling friction, so less force is needed.
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